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9 (nine) is the
natural number In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country"). Numbers used for counting are called ''Cardinal n ...
following and preceding .


Evolution of the Arabic digit

In the
beginning Beginning may refer to: * ''Beginning'' (album), by Pakho Chau * ''Beginning'' (play), a 2017 play by David Eldridge * ''Beginning'' (film), a Georgian-French drama film *"Beginning", a song by heavy metal band Kotipelto *"Beginning", a 2018 trac ...
, various Indians wrote a digit 9 similar in shape to the modern closing
question mark The question mark (also known as interrogation point, query, or eroteme in journalism) is a punctuation mark that indicates an interrogative clause or phrase in many languages. History In the fifth century, Syriac Bible manuscripts used ques ...
without the bottom dot. The Kshatrapa, Andhra and Gupta started curving the bottom vertical line coming up with a -look-alike. The Nagari continued the bottom stroke to make a circle and enclose the 3-look-alike, in much the same way that the sign @ encircles a lowercase ''a''. As time went on, the enclosing circle became bigger and its line continued beyond the circle downwards, as the 3-look-alike became smaller. Soon, all that was left of the 3-look-alike was a squiggle. The Arabs simply connected that squiggle to the downward stroke at the middle and subsequent European change was purely cosmetic. While the shape of the glyph for the digit 9 has an ascender in most modern
typeface A typeface (or font family) is the design of lettering that can include variations in size, weight (e.g. bold), slope (e.g. italic), width (e.g. condensed), and so on. Each of these variations of the typeface is a font. There are list of type ...
s, in typefaces with
text figures Text figures (also known as non-lining, lowercase, old style, ranging, hanging, medieval, billing, or antique figures or numerals) are numerals designed with varying heights in a fashion that resembles a typical line of running text, hence the ...
the character usually has a
descender In typography and handwriting, a descender is the portion of a letter that extends below the baseline of a font. For example, in the letter ''y'', the descender is the "tail", or that portion of the diagonal line which lies below the ''v'' c ...
, as, for example, in . The modern digit resembles an inverted ''6''. To disambiguate the two on objects and documents that can be inverted, they are often underlined. Another distinction from the 6 is that it is sometimes handwritten with two strokes and a straight stem, resembling a raised lower-case letter q. In a
seven-segment display A seven-segment display is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot matrix displays. Seven-segment displays are widely used in digital clocks, electronic meters, basic ...
, the number 9 can be constructed in two ways, either with a hook at the end of its stem or without one. Most LCD calculators use the former, but some
VFD VFD may refer to: * Factory Workers' Union of Germany, (german: Verband der Fabrikarbeiter Deutschlands, link=no), a former trade union in Germany * Vacuum fluorescent display, a display device on consumer electronics equipment * Variable-freque ...
models use the latter.


Mathematics

Nine is the fourth
composite number A composite number is a positive integer that can be formed by multiplying two smaller positive integers. Equivalently, it is a positive integer that has at least one divisor other than 1 and itself. Every positive integer is composite, prime, ...
, and the first composite number that is odd. 9 is the highest single-digit number in the decimal system. It is the third
square number In mathematics, a square number or perfect square is an integer that is the square (algebra), square of an integer; in other words, it is the multiplication, product of some integer with itself. For example, 9 is a square number, since it equals ...
(32), and the second non-unitary square
prime A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...
of the form ''p''2 and first that is odd, with all subsequent squares of this form odd as well. By
Mihăilescu's theorem Catalan's conjecture (or Mihăilescu's theorem) is a theorem in number theory that was conjectured by the mathematician Eugène Charles Catalan in 1844 and proven in 2002 by Preda Mihăilescu at Paderborn University. The integers 23 and 32 are ...
, 9 is the only positive
perfect power In mathematics, a perfect power is a natural number that is a product of equal natural factors, or, in other words, an integer that can be expressed as a square or a higher integer power of another integer greater than one. More formally, ''n'' ...
that is one more than another positive perfect power, since the
square In Euclidean geometry, a square is a regular quadrilateral, which means that it has four equal sides and four equal angles (90-degree angles, π/2 radian angles, or right angles). It can also be defined as a rectangle with two equal-length adj ...
of 3 is one more than the
cube In geometry, a cube is a three-dimensional solid object bounded by six square faces, facets or sides, with three meeting at each vertex. Viewed from a corner it is a hexagon and its net is usually depicted as a cross. The cube is the only r ...
of 2. A number that is 4 or 5 modulo 9 cannot be represented as the
sum of three cubes In the mathematics of sums of powers, it is an open problem to characterize the numbers that can be expressed as a sum of three cubes of integers, allowing both positive and negative cubes in the sum. A necessary condition for n to equal such a ...
. 9 is a
Motzkin number In mathematics, the th Motzkin number is the number of different ways of drawing non-intersecting chords between points on a circle (not necessarily touching every point by a chord). The Motzkin numbers are named after Theodore Motzkin and have d ...
, for the number of ways of drawing non-intersecting
chords Chord may refer to: * Chord (music), an aggregate of musical pitches sounded simultaneously ** Guitar chord a chord played on a guitar, which has a particular tuning * Chord (geometry), a line segment joining two points on a curve * Chord ( ...
between four points on a
circle A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre. Equivalently, it is the curve traced out by a point that moves in a plane so that its distance from a given point is const ...
. Since , 9 is an
exponential factorial The exponential factorial is a positive integer ''n'' raised to the power of ''n'' − 1, which in turn is raised to the power of ''n'' − 2, and so on and so forth in a right-grouping manner. That is, : n^ The expon ...
. Six recurring nines appear in the decimal places 762 through 767 of . (See
six nines in pi A sequence of six consecutive nines occurs in the decimal representation of the number pi (), starting at the 762nd decimal place.. It has become famous because of the mathematical coincidence and because of the idea that one could memorize the d ...
). The first non-trivial
magic square In recreational mathematics, a square array of numbers, usually positive integers, is called a magic square if the sums of the numbers in each row, each column, and both main diagonals are the same. The 'order' of the magic square is the number ...
is a 3 x 3 magic square made of nine cells, with a
magic constant The magic constant or magic sum of a magic square is the sum of numbers in any row, column, or diagonal of the magic square. For example, the magic square shown below has a magic constant of 15. For a normal magic square of order ''n'' – that is ...
of 15; there are no 2 x 2 magic squares with four cells. Meanwhile, a 9 x 9 magic square has a magic constant of 369. A
polygon In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed ''polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two toge ...
with nine sides is called a
nonagon In geometry, a nonagon () or enneagon () is a nine-sided polygon or 9-gon. The name ''nonagon'' is a prefix hybrid formation, from Latin (''nonus'', "ninth" + ''gonon''), used equivalently, attested already in the 16th century in French ''nonogo ...
. Also an ''enneagon'', it is able to fill a plane-vertex alongside an
equilateral triangle In geometry, an equilateral triangle is a triangle in which all three sides have the same length. In the familiar Euclidean geometry, an equilateral triangle is also equiangular; that is, all three internal angles are also congruent to each othe ...
and an regular
octadecagon In geometry, an octadecagon (or octakaidecagon) or 18-gon is an eighteen-sided polygon. Regular octadecagon A '' regular octadecagon'' has a Schläfli symbol and can be constructed as a quasiregular truncated enneagon, t, which alternates tw ...
, or 18-sided
polygon In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed ''polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two toge ...
. There are nine distinct
uniform coloring In geometry, a uniform coloring is a property of a uniform figure (uniform tiling or uniform polyhedron) that is colored to be vertex-transitive. Different symmetries can be expressed on the same geometric figure with the faces following differ ...
s of the
triangular tiling In geometry, the triangular tiling or triangular tessellation is one of the three regular tilings of the Euclidean plane, and is the only such tiling where the constituent shapes are not parallelogons. Because the internal angle of the equilater ...
and the
square tiling In geometry, the square tiling, square tessellation or square grid is a regular tiling of the Euclidean plane. It has Schläfli symbol of meaning it has 4 squares around every vertex. Conway called it a quadrille. The internal angle of th ...
, which are the two simplest
regular tilings This article lists the regular polytopes and regular polytope compounds in Euclidean geometry, Euclidean, spherical geometry, spherical and hyperbolic geometry, hyperbolic spaces. The Schläfli symbol describes every regular tessellation of an ' ...
; the
hexagonal tiling In geometry, the hexagonal tiling or hexagonal tessellation is a regular tiling of the Euclidean plane, in which exactly three hexagons meet at each vertex. It has Schläfli symbol of or (as a truncated triangular tiling). English mathemat ...
, on the other hand, has three distinct uniform colorings. There are nine
edge-transitive In geometry, a polytope (for example, a polygon or a polyhedron) or a tiling is isotoxal () or edge-transitive if its symmetries act transitively on its edges. Informally, this means that there is only one type of edge to the object: given two ...
convex polyhedra in
three dimensions Three-dimensional space (also: 3D space, 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called ''parameters'') are required to determine the position of an element (i.e., point). This is the informa ...
: *the five regular Platonic solids: the
tetrahedron In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. The tetrahedron is the simplest of all the o ...
,
octahedron In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at ea ...
,
cube In geometry, a cube is a three-dimensional solid object bounded by six square faces, facets or sides, with three meeting at each vertex. Viewed from a corner it is a hexagon and its net is usually depicted as a cross. The cube is the only r ...
,
dodecahedron In geometry, a dodecahedron (Greek , from ''dōdeka'' "twelve" + ''hédra'' "base", "seat" or "face") or duodecahedron is any polyhedron with twelve flat faces. The most familiar dodecahedron is the regular dodecahedron with regular pentagon ...
and
icosahedron In geometry, an icosahedron ( or ) is a polyhedron with 20 faces. The name comes and . The plural can be either "icosahedra" () or "icosahedrons". There are infinitely many non- similar shapes of icosahedra, some of them being more symmetrica ...
; *the two quasiregular
Archimedean solid In geometry, an Archimedean solid is one of the 13 solids first enumerated by Archimedes. They are the convex uniform polyhedra composed of regular polygons meeting in identical vertices, excluding the five Platonic solids (which are composed ...
s: the
cuboctahedron A cuboctahedron is a polyhedron with 8 triangular faces and 6 square faces. A cuboctahedron has 12 identical vertices, with 2 triangles and 2 squares meeting at each, and 24 identical edges, each separating a triangle from a square. As such, it ...
and the
icosidodecahedron In geometry, an icosidodecahedron is a polyhedron with twenty (''icosi'') triangular faces and twelve (''dodeca'') pentagonal faces. An icosidodecahedron has 30 identical vertices, with two triangles and two pentagons meeting at each, and 60 id ...
; and *two
Catalan solid In mathematics, a Catalan solid, or Archimedean dual, is a dual polyhedron to an Archimedean solid. There are 13 Catalan solids. They are named for the Belgian mathematician Eugène Catalan, who first described them in 1865. The Catalan sol ...
s: the
rhombic dodecahedron In geometry, the rhombic dodecahedron is a convex polyhedron with 12 congruent rhombic faces. It has 24 edges, and 14 vertices of 2 types. It is a Catalan solid, and the dual polyhedron of the cuboctahedron. Properties The rhombic dodecahedro ...
and the
rhombic triacontahedron In geometry, the rhombic triacontahedron, sometimes simply called the triacontahedron as it is the most common thirty-faced polyhedron, is a convex polyhedron with 30 rhombic faces. It has 60 edges and 32 vertices of two types. It is a Cata ...
, which are
duals ''Duals'' is a compilation album by the Irish rock band U2. It was released in April 2011 to u2.com subscribers. Track listing :* "Where the Streets Have No Name" and "Amazing Grace" are studio mix of U2's performance at the Rose Bowl, Pas ...
to the only two quasiregular polyhedra. In
four-dimensional space A four-dimensional space (4D) is a mathematical extension of the concept of three-dimensional or 3D space. Three-dimensional space is the simplest possible abstraction of the observation that one only needs three numbers, called ''dimensions'', ...
, there are nine paracompact hyperbolic honeycomb
Coxeter group In mathematics, a Coxeter group, named after H. S. M. Coxeter, is an abstract group that admits a formal description in terms of reflections (or kaleidoscopic mirrors). Indeed, the finite Coxeter groups are precisely the finite Euclidean refl ...
s, as well as nine regular compact hyperbolic honeycombs from regular
convex Convex or convexity may refer to: Science and technology * Convex lens, in optics Mathematics * Convex set, containing the whole line segment that joins points ** Convex polygon, a polygon which encloses a convex set of points ** Convex polytope ...
and
star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
'' polychora''. There are also nine uniform demitesseractic (\mathrm D_) Euclidean honeycombs in the fourth dimension. There are only three types of
Coxeter groups In mathematics, a Coxeter group, named after Harold Scott MacDonald Coxeter, H. S. M. Coxeter, is an group (mathematics), abstract group that admits a group presentation, formal description in terms of Reflection (mathematics), reflections (or Kal ...
of uniform figures in dimensions
nine 9 is a number, numeral, and glyph. 9 or nine may also refer to: Dates * AD 9, the ninth year of the AD era * 9 BC, the ninth year before the AD era * 9, numerical symbol for the month of September Places * Nine, Portugal, a parish in the ...
and thereafter, aside from the many families of prisms and
proprism In geometry of 4 dimensions or higher, a proprism is a polytope resulting from the Cartesian product of two or more polytopes, each of two dimensions or higher. The term was coined by John Horton Conway for ''product prism''. The dimension of the s ...
s: the \mathrm A_
simplex In geometry, a simplex (plural: simplexes or simplices) is a generalization of the notion of a triangle or tetrahedron to arbitrary dimensions. The simplex is so-named because it represents the simplest possible polytope in any given dimension. ...
groups, the \mathrm B_
hypercube In geometry, a hypercube is an ''n''-dimensional analogue of a square () and a cube (). It is a closed, compact, convex figure whose 1- skeleton consists of groups of opposite parallel line segments aligned in each of the space's dimensions, ...
groups, and the \mathrm D_
demihypercube In geometry, demihypercubes (also called ''n-demicubes'', ''n-hemicubes'', and ''half measure polytopes'') are a class of ''n''- polytopes constructed from alternation of an ''n''- hypercube, labeled as ''hγn'' for being ''half'' of the hy ...
groups. The ninth dimension is also the final dimension that contains Coxeter-Dynkin diagrams as uniform solutions in
hyperbolic space In mathematics, hyperbolic space of dimension n is the unique simply connected, n-dimensional Riemannian manifold of constant sectional curvature equal to -1. It is homogeneous, and satisfies the stronger property of being a symmetric space. Th ...
. Inclusive of compact hyperbolic solutions, there are a total of 238 compact and paracompact Coxeter-Dynkin diagrams between dimensions two and nine, or equivalently between ranks three and ten. The most important of the last _9 paracompact groups is the group _9 with 1023 total honeycombs, the simplest of which is 621 whose
vertex figure In geometry, a vertex figure, broadly speaking, is the figure exposed when a corner of a polyhedron or polytope is sliced off. Definitions Take some corner or Vertex (geometry), vertex of a polyhedron. Mark a point somewhere along each connect ...
is the 521 honeycomb: the vertex arrangement of the densest-possible packing of spheres in 8 dimensions which forms the \mathbb E_ lattice. The 621 honeycomb is made of
9-simplex In geometry, a 9- simplex is a self-dual regular 9-polytope. It has 10 vertices, 45 edges, 120 triangle faces, 210 tetrahedral cells, 252 5-cell 4-faces, 210 5-simplex 5-faces, 120 6-simplex 6-faces, 45 7-simplex 7-faces, and 10 8-simplex 8-fa ...
es and
9-orthoplex In geometry, a 9-orthoplex or 9-cross polytope, is a regular 9-polytope with 18 vertices, 144 edges, 672 triangle faces, 2016 tetrahedron cells, 4032 5-cells ''4-faces'', 5376 5-simplex ''5-faces'', 4608 6-simplex ''6-faces'', 2304 7-simplex '' ...
es, with 1023 total polytope elements making up each 9-simplex. It is the final honeycomb figure with infinite facets and vertex figures in the k21 family of
semiregular polytope In geometry, by Thorold Gosset's definition a semiregular polytope is usually taken to be a polytope that is vertex-transitive and has all its facets being regular polytopes. E.L. Elte compiled a longer list in 1912 as ''The Semiregular Polyt ...
s, first defined by
Thorold Gosset John Herbert de Paz Thorold Gosset (16 October 1869 – December 1962) was an English lawyer and an amateur mathematician. In mathematics, he is noted for discovering and classifying the semiregular polytopes in dimensions four and higher, and ...
in 1900. There are nine
Heegner number In number theory, a Heegner number (as termed by Conway and Guy) is a square-free positive integer ''d'' such that the imaginary quadratic field \Q\left sqrt\right/math> has class number 1. Equivalently, its ring of integers has unique factoriza ...
s, or square-free positive integers n that yield an imaginary
quadratic field In algebraic number theory, a quadratic field is an algebraic number field of degree two over \mathbf, the rational numbers. Every such quadratic field is some \mathbf(\sqrt) where d is a (uniquely defined) square-free integer different from 0 an ...
\Q\left sqrt\right/math> whose
ring of integers In mathematics, the ring of integers of an algebraic number field K is the ring of all algebraic integers contained in K. An algebraic integer is a root of a monic polynomial with integer coefficients: x^n+c_x^+\cdots+c_0. This ring is often deno ...
has a
unique factorization In mathematics, a unique factorization domain (UFD) (also sometimes called a factorial ring following the terminology of Bourbaki) is a ring in which a statement analogous to the fundamental theorem of arithmetic holds. Specifically, a UFD is a ...
, or class number of 1.


In decimal

A positive number is divisible by nine
if and only if In logic and related fields such as mathematics and philosophy, "if and only if" (shortened as "iff") is a biconditional logical connective between statements, where either both statements are true or both are false. The connective is bicondi ...
its
digital root The digital root (also repeated digital sum) of a natural number in a given radix is the (single digit) value obtained by an iterative process of summing digits, on each iteration using the result from the previous iteration to compute a digit su ...
is nine. That is, if any
natural number In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country"). Numbers used for counting are called ''Cardinal n ...
is multiplied by 9, and the digits of the answer are repeatedly added until it is just one digit, the sum will be nine: *2 × 9 = 18 (1 + 8 = 9) *3 × 9 = 27 (2 + 7 = 9) *9 × 9 = 81 (8 + 1 = 9) *121 × 9 = 1089 (1 + 0 + 8 + 9 = 18; 1 + 8 = 9) *234 × 9 = 2106 (2 + 1 + 0 + 6 = 9) *578329 × 9 = 5204961 (5 + 2 + 0 + 4 + 9 + 6 + 1 = 27; 2 + 7 = 9) *482729235601 × 9 = 4344563120409 (4 + 3 + 4 + 4 + 5 + 6 + 3 + 1 + 2 + 0 + 4 + 0 + 9 = 45; 4 + 5 = 9) There are other interesting patterns involving multiples of nine: *12345679 × 9 = 111111111 *12345679 × 18 = 222222222 *12345679 × 81 = 999999999 This works for all the multiples of 9. is the only other such that a number is divisible by ''n'' if and only if its digital root is divisible by ''n''. In base-''N'', the
divisor In mathematics, a divisor of an integer n, also called a factor of n, is an integer m that may be multiplied by some integer to produce n. In this case, one also says that n is a multiple of m. An integer n is divisible or evenly divisible by ...
s of have this property. Another consequence of 9 being , is that it is also a
Kaprekar number In mathematics, a natural number in a given number base is a p-Kaprekar number if the representation of its square in that base can be split into two parts, where the second part has p digits, that add up to the original number. The numbers are n ...
. The difference between a base-10 positive integer and the sum of its digits is a whole multiple of nine. Examples: *The sum of the digits of 41 is 5, and 41 − 5 = 36. The digital root of 36 is 3 + 6 = 9, which, as explained above, demonstrates that it is divisible by nine. *The sum of the digits of 35967930 is 3 + 5 + 9 + 6 + 7 + 9 + 3 + 0 = 42, and 35967930 − 42 = 35967888. The digital root of 35967888 is 3 + 5 + 9 + 6 + 7 + 8 + 8 + 8 = 54, 5 + 4 = 9. If dividing a number by the amount of 9s corresponding to its number of digits, the number is turned into a
repeating decimal A repeating decimal or recurring decimal is decimal representation of a number whose digits are periodic (repeating its values at regular intervals) and the infinitely repeated portion is not zero. It can be shown that a number is rational if an ...
. (e.g. )
Casting out nines Casting out nines is any of three arithmetical procedures: *Adding the decimal digits of a positive whole number, while optionally ignoring any 9s or digits which sum to a multiple of 9. The result of this procedure is a number which is smaller th ...
is a quick way of testing the calculations of sums, differences, products, and quotients of integers known as long ago as the 12th century.


List of basic calculations


Alphabets and codes

*In the
NATO phonetic alphabet The (International) Radiotelephony Spelling Alphabet, commonly known as the NATO phonetic alphabet, is the most widely used set of clear code words for communicating the letters of the Roman alphabet, technically a ''radiotelephonic spellin ...
, the digit 9 is called "Niner". *Five-digit produce Price Look-Up code, PLU codes that begin with 9 are Organic food, organic.


Culture and mythology


Indian culture

Nine is a number that appears often in Indian culture and mythology. Some instances are enumerated below. *Nine Navagraha, influencers are attested in Indian astrology. *In the Vaisheshika branch of Hindu philosophy, there are nine universal substances or elements: Prithvi, Earth, Ap (water), Water, Vayu, Air, Agni, Fire, Akasha, Ether, Kāla (time), Time, Vaisheshika#The Categories or Pad.C4.81rtha, Space, Ātman (Hinduism), Soul, and Manas (early Buddhism), Mind. *Navaratri is a nine-day festival dedicated to the Navadurga, nine forms of Durga. *Navaratna, meaning "nine jewels" may also refer to Navaratnas – accomplished courtiers, Korma#Navratan korma, Navratan – a kind of dish, or a form of Navaratna (architecture), architecture. *In Indian aesthetics, there are nine kinds of Rasa (aesthetics), Rasa.


Chinese culture

*Nine ( pinyin jiǔ) is considered a good Numbers in Chinese culture, number in Chinese culture because it sounds the same as the word "long-lasting" ( pinyin jiǔ). *Nine is strongly associated with the Chinese dragon, a symbol of magic and power. There are nine forms of the dragon, it is described in terms of nine attributes, and it has nine children. It has 117 scales – 81 yin and yang, yang (masculine, heavenly) and 36 yin and yang, yin (feminine, earthly). All three numbers are multiples of 9 (, , ) as well as having the same
digital root The digital root (also repeated digital sum) of a natural number in a given radix is the (single digit) value obtained by an iterative process of summing digits, on each iteration using the result from the previous iteration to compute a digit su ...
of 9. *The dragon often symbolizes the Emperor of China, Emperor, and the number nine can be found in many ornaments in the Forbidden City. *The circular altar platform (''Earthly Mount'') of the Temple of Heaven has one circular marble plate in the center, surrounded by a ring of nine plates, then by a ring of 18 plates, and so on, for a total of nine rings, with the outermost having *The name of the area called ''Kowloon'' in Hong Kong literally means: ''nine Chinese dragon, dragons''. *The nine-dotted line () delimits certain island Territorial disputes in the South China Sea, claims by China in the South China Sea. *The nine-rank system was a civil service nomination system used during certain Chinese dynasties. *9 Points of the Heart (Healing, Heal) / Heart Master (Immortality) Channels in Traditional Chinese Medicine.


Ancient Egypt

*The nine bows is a term used in Ancient Egypt to represent the traditional enemies of Egypt. *The Ennead is a group of nine Egyptian deities, who, in some versions of the Osiris myth, judged whether Horus or Set (mythology), Set should inherit Egypt.


European culture

*The Nine Worthies are nine historical, or semi-legendary figures who, in the Middle Ages, were believed to personify the ideals of chivalry. *In Norse mythology, the universe is divided into Norse cosmology, nine worlds which are all connected by the world tree Yggdrasil *In Norse mythology as well, the number nine is associated with Odin, as that is how many days he hung from the world tree Yggdrasil before attaining knowledge of the runes.


Greek mythology

*The nine Muses in Greek mythology are Calliope (epic poetry), Clio (history), Erato (erotic poetry), Euterpe (lyric poetry), Melpomene (tragedy), Polyhymnia (song), Terpsichore (dance), Thalia (Muse), Thalia (comedy), and Urania (astronomy). *It takes nine days (for an anvil) to fall from heaven to earth, and nine more to fall from earth to Tartarus. *Leto labored for nine days and nine nights for Apollo, according to the Homeric Hymn, Homeric Hymn to Delian Apollo.


Mesoamerican mythology

* The Lords of the Night, is a group of nine deities who each ruled over every ninth night forming a calendrical cycle


Aztec mythology

* Mictlan the underworld in Aztec mythology, consists of nine levels.


Mayan mythology

* The Mayan underworld Xibalba consists of nine levels. * El Castillo, Chichen Itza, El Castillo the Mayan step-pyramid in Chichén Itzá, consists of nine steps. It is said that this was done to represent the nine levels of Xibalba.


Anthropology


Idioms

*"to go the whole nine yards-" *"A cat-o'-nine-tails suggests perfect punishment and atonement." – Robert Ripley. *"A cat has nine lives" *"to be on cloud nine" *"A stitch in time saves nine" *"found true 9 out of 10 times" *"possession is nine tenths of the law" *The word "K-9" pronounces the same as ''canine'' and is used in many US police departments to denote the police dog unit. Despite not sounding like the translation of the word ''canine'' in other languages, many police and military units around the world use the same designation. *Someone dressed "to the nines" is dressed up as much as they can be. *In North American urban culture, "nine" is a slang word for a 9mm pistol or homicide, the latter from the Illinois Criminal Code for homicide.


Society

*''The 9 on Yahoo!'', hosted by Maria Sansone, was a daily video compilation show, or vlog, on Yahoo! featuring the nine top "web finds" of the day. *Nine justices sit on the United States Supreme Court. *Nine justices sit on the Supreme Court of Canada.


Technique

*Stanines, a method of scaling test scores, range from 1 to 9. *There are 9 Square foot, square feet in a square yard.


Pseudoscience

* In Pythagorean numerology the number 9 symbolizes the end of one cycle and the beginning of another.


Literature

*There are Divine Comedy#The Circles of Hell, nine circles of Hell in Dante's ''Divine Comedy''. *The Nine Bright Shiners, characters in Garth Nix's Old Kingdom trilogy. ''The Nine Bright Shiners'' was a 1930s book of poems by Anne Ridler and a 1988 fiction book by Anthea Fraser; the name derives from "a very curious old semi-pagan, semi-Christian" song. *''The Nine Tailors'' is a 1934 mystery novel by British writer Dorothy L. Sayers, her ninth featuring sleuth Lord Peter Wimsey. *Nine Unknown Men are, in occult legend, the custodians of the sciences of the world since ancient times. *In J. R. R. Tolkien's Middle-earth, there are nine rings of power given to men, and consequently, nine Nazgûl, ringwraiths. Additionally, The Fellowship of the Ring#Members of the Fellowship of the Ring, The Fellowship of the Ring consists of nine companions. *In ''Lorien Legacies'' there are nine Garde sent to Earth. *Number Nine is a character in ''Lorien Legacies''. *In the series ''A Song of Ice and Fire'', there are nine regions of Westeros (the Crownlands, the North, the Riverlands, the Westerlands, the Reach, the Stormlands, the Vale of Arryn, the Iron Islands and Dorne). Additionally, there is a group of nine city-states in western Essos known collectively as the Free Cities (Braavos, Lorath, Lys, Myr, Norvos, Pentos, Qohor, Tyrosh and Volantis). *In ''The Wheel of Time'' series, Daughter of the Nine Moons is the title given to the heir to the throne of Seanchan, and the Court of the Nine Moons serves as the throne room of the Seanchan rulers themselves. Additionally, the nation of Illian is partially governed by a body known as the Council of Nine, and the flag of Illian displays nine golden bees on it. Furthermore, in the Age of Legends, the Nine Rods of Dominion were nine regional governors who administered individual areas of the world under the ruling world government.


Organizations

*Divine Nine – The National Pan-Hellenic Council (NPHC) is a collaborative organization of nine historically African American, international Greek-lettered fraternities and sororities.


Places and thoroughfares

*List of highways numbered 9 *Ninth Avenue (Manhattan), Ninth Avenue is a major avenue in Manhattan. *Provinces of South Africa, South Africa has 9 provinces * Negeri Sembilan, a Malaysian States in Malaysia, state located in Peninsular Malaysia, is named as such as it was historically a confederation of nine ( ms, sembilan) settlements (''nagari (settlement), nagari'') of the Minangkabau people, Minangkabau migrated from West Sumatra.


Religion and philosophy

*Nine, as the highest single-digit number (in decimal, base ten), symbolizes completeness in the Baháʼí Faith. In addition, the word Baháʼ in the Abjad numerals, Abjad notation has a value of 9, and a 9-pointed star is used to Baháʼí symbols, symbolize the religion. *The number 9 is revered in Hinduism and considered a complete, perfected and divine number because it represents the end of a cycle in the decimal system, which originated from the Indian subcontinent as early as 30th century BC, 3000 BC. *In Buddhism, Gautama Buddha was believed to have nine virtues, which he was (1) Accomplished, (2) Perfectly Enlightened, (3) Endowed with knowledge and Conduct or Practice, (4) Well-gone or Well-spoken, (5) the Knower of worlds, (6) the Guide Unsurpassed of men to be tamed, (7) the Teacher of gods and men, (8) Enlightened, and (9) Blessed. *Important Buddhist rituals usually involve nine monks. *The first nine days of the Hebrew calendar, Hebrew month of Av (month), Av are collectively known as "The Nine Days" (''Tisha HaYamim''), and are a period of semi-mourning leading up to Tisha B'Av, the ninth day of Av on which both Temple in Jerusalem, Temples in Jerusalem were destroyed. *Nine is a significant number in Norse Mythology. Odin hung himself on an ash tree for nine days to learn the runes. *The Fourth Way Enneagram is one system of knowledge which shows the correspondence between the 9 integers and the circle. *In the Christian angelic hierarchy there are 9 choirs of angels. *Ramadan (calendar month), Ramadan, the month of fasting and prayer, is the ninth month of the Islamic calendar. *Tian's Trigram Number, of Feng Shui, in Taoism. *In Christianity there are nine Fruit of the Holy Spirit which followers are expected to have: love, joy, peace, forbearance, patience, kindness, Good and evil, goodness, faithfulness, gentleness, and self-control. *The Bible recorded that Christ died at the 9th hour of the day (3 pm).


Science


Astronomy

*Before 2006 (when Pluto was Pluto#2006: IAU classification, officially designated as a non-planet), there were nine planets in the Solar System. *Messier object Messier 9, M9 is a magnitude 9.0 globular cluster in the constellation Ophiuchus. *The New General Catalogue]
object
NGC 9, a spiral galaxy in the constellation Pegasus (constellation), Pegasus.


Chemistry

*The purity of chemicals (see Nine (purity)). *Nine is the atomic number of fluorine.


Physiology

A human pregnancy normally lasts nine months, the basis of Naegele's rule.


Psychology

Common terminal digit in psychological pricing.


Sports

*Nine-ball is the standard professional pocket billiards variant played in the United States. *In association football (soccer), the centre-forward/striker traditionally (since at least the fifties) wears the number 9 shirt. *In baseball: **There are nine players on the field including the pitcher. **There are nine innings in a standard game. **9 represents the right fielder's position. **''NINE: A Journal of Baseball History and Culture'', published by the University of Nebraska Press *In rugby league, the jersey number assigned to the Hooker (rugby league), hooker in most competitions. (An exception is the Super League, which uses static squad numbering.) *In rugby union, the number worn by the starting Scrum-half (rugby union), scrum-half.


Technology

*ISO 9 is the International Organization for Standardization, ISO's standard for the transliteration of Cyrillic characters into Latin characters *In the Rich Text Format specification, 9 is the language code for the English language. All codes for regional variants of English are congruent to 9 mod 256. *The9 Limited (owner o
the9.com
is a company in the video-game industry, including former ties to the extremely popular MMORPG World of Warcraft.


Music

*"Revolution 9", a sound collage which appears on The Beatles' eponymous 1968 album The Beatles (album), ''The Beatles'' (aka ''The White Album''), prominently features a loop of a man's voice repeating the phrase "Number nine". *There are 9 semitones in a Major 6th interval in music. *There was a Curse of the ninth, superstition among some notable classical music composers that they would die after completing their ninth symphony. Some composers who died after composing their ninth symphony include Ludwig van Beethoven, Anton Bruckner, Antonin Dvorak and Gustav Mahler.


See also

*9 (disambiguation) *0.999... *wikt:cloud nine, Cloud Nine *List of highways numbered 9


References


Further reading

*Cecil Balmond, "Number 9, the search for the sigma code" 1998, Prestel 2008, , {{DEFAULTSORT:9 (Number) Integers 9 (number) Superstitions about numbers