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 ...
prime number
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 ...
prime number
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 ...
in the series of
positive integers
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 ...
, the number seven has greatly symbolic associations in
religion
Religion is usually defined as a social- cultural system of designated behaviors and practices, morals, beliefs, worldviews, texts, sanctified places, prophecies, ethics, or organizations, that generally relates humanity to supernatural, ...
,
mythology
Myth is a folklore genre consisting of narratives that play a fundamental role in a society, such as foundational tales or origin myths. Since "myth" is widely used to imply that a story is not objectively true, the identification of a narra ...
Classical planet
In classical antiquity, the seven classical planets or seven luminaries are the seven moving astronomical objects in the sky visible to the naked eye: the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and Saturn. The word ''planet'' comes fro ...
s resulted in seven being the number of days in a week. It is often considered
luck
Luck is the phenomenon and belief that defines the experience of improbable events, especially improbably positive or negative ones. The naturalistic interpretation is that positive and negative events may happen at any time, both due to rand ...
y in
Western culture
Leonardo da Vinci's ''Vitruvian Man''. Based on the correlations of ideal Body proportions">human proportions with geometry described by the ancient Roman architect Vitruvius in Book III of his treatise ''De architectura''.
image:Plato Pio-Cle ...
Western culture
Leonardo da Vinci's ''Vitruvian Man''. Based on the correlations of ideal Body proportions">human proportions with geometry described by the ancient Roman architect Vitruvius in Book III of his treatise ''De architectura''.
image:Plato Pio-Cle ...
, in
Vietnamese culture
The culture of Vietnam (Vietnamese: Văn hoá Việt Nam) is highly multicultural. The early culture in Vietnam started with the Bronze Age Đông Sơn culture considered to be one of its most important progenitors for its Ancient history. Vie ...
, the number seven is sometimes considered unlucky.
It is the first natural number whose pronunciation contains more than one syllable.
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 ...
, Indians wrote 7 more or less in one stroke as a curve that looks like an uppercase vertically inverted. The western Ghubar Arabs' main contribution was to make the longer line diagonal rather than straight, though they showed some tendencies to making the digit more rectilinear. The eastern
Arab
The Arabs (singular: Arab; singular ar, عَرَبِيٌّ, DIN 31635: , , plural ar, عَرَب, DIN 31635: , Arabic pronunciation: ), also known as the Arab people, are an ethnic group mainly inhabiting the Arab world in Western Asia, ...
s developed the digit from a form that looked something like our 6 to one that looked like an uppercase V. Both modern Arab forms influenced the European form, a two-stroke form consisting of a horizontal upper stroke joined at its right to a stroke going down to the bottom left corner, a line that is slightly curved in some font variants. As is the case with the
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
an digit, the Cham and Khmer digit for 7 also evolved to look like their digit 1, though in a different way, so they were also concerned with making their 7 more different. For the Khmer this often involved adding a horizontal line to the top of the digit. This is analogous to the horizontal stroke through the middle that is sometimes used in handwriting in the Western world but which is almost never used in computer fonts. This horizontal stroke is, however, important to distinguish the glyph for seven from the glyph for one in writing that uses a long upstroke in the glyph for 1. In some Greek dialects of the early 12th century the longer line diagonal was drawn in a rather semicircular transverse line.
On the
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 ...
s of pocket calculators and digital watches, 7 is the digit with the most common graphic variation (1, 6 and 9 also have variant glyphs). Most calculators use three line segments, but on
Sharp
Sharp or SHARP may refer to:
Acronyms
* SHARP (helmet ratings) (Safety Helmet Assessment and Rating Programme), a British motorcycle helmet safety rating scheme
* Self Help Addiction Recovery Program, a charitable organisation founded in 19 ...
,
Casio
is a Japanese multinational electronics manufacturing corporation headquartered in Shibuya, Tokyo, Japan. Its products include calculators, mobile phones, digital cameras, electronic musical instruments, and analogue and digital watches. I ...
, and a few other brands of calculators, 7 is written with four line segments because in Japan, Korea and Taiwan 7 is written with a "hook" on the left, as ① in the following illustration.
While the shape of the character for the digit 7 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 thousands o ...
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 .
Most people in Continental Europe, and some in Britain and Ireland as well as Latin America, write 7 with a line in the middle ("7"), sometimes with the top line crooked. The line through the middle is useful to clearly differentiate the digit from the digit one, as the two can appear similar when written in certain styles of handwriting. This form is used in official handwriting rules for primary school in Russia, Ukraine, Bulgaria, Poland, other Slavic countries, France, Italy, Belgium, Finland, Romania, Germany, Greece, and Hungary.
Mathematics
Seven, the fourth
prime number
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 ...
, is not only a
Mersenne prime
In mathematics, a Mersenne prime is a prime number that is one less than a power of two. That is, it is a prime number of the form for some integer . They are named after Marin Mersenne, a French Minim friar, who studied them in the early 17th ...
(since ) but also a
double Mersenne prime
In mathematics, a double Mersenne number is a Mersenne number of the form
:M_ = 2^-1
where ''p'' is prime.
Examples
The first four terms of the sequence of double Mersenne numbers areChris Caldwell''Mersenne Primes: History, Theorems and ...
Woodall prime
In number theory, a Woodall number (''W'n'') is any natural number of the form
:W_n = n \cdot 2^n - 1
for some natural number ''n''. The first few Woodall numbers are:
:1, 7, 23, 63, 159, 383, 895, … .
History
Woodall numbers were first st ...
lucky prime
In number theory, a lucky number is a natural number in a set which is generated by a certain "sieve". This sieve is similar to the Sieve of Eratosthenes that generates the primes, but it eliminates numbers based on their position in the remain ...
, a
happy number
In number theory, a happy number is a number which eventually reaches 1 when replaced by the sum of the square of each digit. For instance, 13 is a happy number because 1^2+3^2=10, and 1^2+0^2=1. On the other hand, 4 is not a happy number because ...
(happy prime), a
safe prime
In number theory, a prime number ''p'' is a if 2''p'' + 1 is also prime. The number 2''p'' + 1 associated with a Sophie Germain prime is called a . For example, 11 is a Sophie Germain prime and 2 × 11 +  ...
aliquot sum
In number theory, the aliquot sum ''s''(''n'') of a positive integer ''n'' is the sum of all proper divisors of ''n'', that is, all divisors of ''n'' other than ''n'' itself.
That is,
:s(n)=\sum\nolimits_d.
It can be used to characterize the prime ...
of one number, the
cubic number
In arithmetic and algebra, the cube of a number is its third power, that is, the result of multiplying three instances of together.
The cube of a number or any other mathematical expression is denoted by a superscript 3, for example or .
...
and is the base of the 7-aliquot tree.
*7 is the only number ''D'' for which the equation has more than two solutions for ''n'' and ''x'' natural. In particular, the equation is known as the
Ramanujan–Nagell equation In mathematics, in the field of number theory, the Ramanujan–Nagell equation is an equation between a square number and a number that is seven less than a power of two. It is an example of an exponential Diophantine equation, an equation to be ...
.
*7 is the only dimension, besides the familiar 3, in which a vector cross product can be defined.
*7 is the lowest
dimension
In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. Thus, a line has a dimension of one (1D) because only one coor ...
of a known exotic sphere, although there may exist as yet unknown exotic smooth structures on the 4-dimensional sphere.
* divided by 7 is exactly . Therefore, when a
vulgar fraction
A fraction (from la, fractus, "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight ...
with 7 in the
denominator
A fraction (from la, fractus, "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight ...
is converted to a decimal expansion, the result has the same six- digit repeating sequence after the decimal point, but the sequence can start with any of those six digits. For example, and
:In fact, if one sorts the digits in the number 142,857 in ascending order, 124578, it is possible to know from which of the digits the decimal part of the number is going to begin with. The remainder of dividing any number by 7 will give the position in the sequence 124578 that the decimal part of the resulting number will start. For example, 628 ÷ 7 = ; here 5 is the remainder, and would correspond to number 7 in the ranking of the ascending sequence. So in this case, . Another example, , hence the remainder is 2, and this corresponds to number 2 in the sequence. In this case, .
*A seven-sided shape is a
heptagon
In geometry, a heptagon or septagon is a seven-sided polygon or 7-gon.
The heptagon is sometimes referred to as the septagon, using "sept-" (an elision of ''septua-'', a Latin-derived numerical prefix, rather than '' hepta-'', a Greek-derived nu ...
. The regular ''n''-gons for ''n'' ≤ 6 can be constructed by compass and straightedge alone, but the regular heptagon cannot.
Figurate number
The term figurate number is used by different writers for members of different sets of numbers, generalizing from triangular numbers to different shapes (polygonal numbers) and different dimensions (polyhedral numbers). The term can mean
* polyg ...
s representing heptagons (including seven) are called
heptagonal number A heptagonal number is a figurate number that is constructed by combining heptagons with ascending size. The ''n''-th heptagonal number is given by the formula
:H_n=\frac.
The first few heptagonal numbers are:
: 0, 1, 7, 18, 34, 55, 81, 112 ...
frieze group
In mathematics, a frieze or frieze pattern is a two-dimensional design that repeats in one direction. Such patterns occur frequently in architecture and decorative art. Frieze patterns can be classified into seven types according to their symmetrie ...
s, the
groups
A group is a number of persons or things that are located, gathered, or classed together.
Groups of people
* Cultural group, a group whose members share the same cultural identity
* Ethnic group, a group whose members share the same ethnic ide ...
consisting of symmetries of the plane whose group of
translations
Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (which does not exist in every language) between ''transl ...
integer
An integer is the number zero (), a positive natural number (, , , etc.) or a negative integer with a minus sign ( −1, −2, −3, etc.). The negative numbers are the additive inverses of the corresponding positive numbers. In the languag ...
s.
*There are seven fundamental types of catastrophes.
*When rolling two standard six-sided dice, seven has a 6 in 6 (or ) probability of being rolled (1–6, 6–1, 2–5, 5–2, 3–4, or 4–3), the greatest of any number. The opposite sides of a standard six-sided dice always add to 7.
*The
Millennium Prize Problems
The Millennium Prize Problems are seven well-known complex mathematical problems selected by the Clay Mathematics Institute in 2000. The Clay Institute has pledged a US$1 million prize for the first correct solution to each problem. According ...
ROYGBIV
ROYGBIV is an acronym for the sequence of hues commonly described as making up a rainbow: red, orange, yellow, green, blue, indigo, and violet. There are several mnemonics that can be used for remembering this color sequence, such as the ...
* Seven
Continent
A continent is any of several large landmasses. Generally identified by convention rather than any strict criteria, up to seven geographical regions
In geography, regions, otherwise referred to as zones, lands or territories, are areas t ...
s
*
Seven Seas
The "Seven Seas" is a figurative term for all the seas of the known world. The phrase is used in reference to sailors and pirates in the arts and popular culture and can be associated with the Mediterranean Sea, the Arabian Seven Seas east of Af ...
*
Seven climes
The climes (singular ''clime''; also ''clima'', plural ''climata'', from Greek κλίμα ''klima'', plural κλίματα ''klimata'', meaning "inclination" or "slope") in classical Greco-Roman geography and astronomy were the divisions of ...
* The neutral pH balance
* Number of music notes in a scale
* Number of spots most commonly found on ladybugs
* Atomic number for
Nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
working memory
Working memory is a cognitive system with a limited capacity that can hold information temporarily. It is important for reasoning and the guidance of decision-making and behavior. Working memory is often used synonymously with short-term memory, ...
.
* Seven psychological types called the Seven Rays in the teachings of Alice A. Bailey
* In Western Culture, Seven is consistently listed as people's favorite number.
* When guessing numbers 1-10 the number 7 is most likely to be picked.
* Seven-year itch: happiness in marriage said to decline after 7 years
Classical antiquity
The
Pythagoreans
Pythagoreanism originated in the 6th century BC, based on and around the teachings and beliefs held by Pythagoras and his followers, the Pythagoreans. Pythagoras established the first Pythagorean community in the ancient Greek colony of Kroton, ...
invested particular numbers with unique spiritual properties. The number seven was considered to be particularly interesting because it consisted of the union of the physical (number 4) with the spiritual (number 3). In Pythagorean numerology the number 7 means spirituality.
References from classical antiquity to the number seven include:
*Seven
Classical planets
In classical antiquity, the seven classical planets or seven luminaries are the seven moving astronomical objects in the sky visible to the naked eye: the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and Saturn. The word ''planet'' comes from ...
Seven Wonders of the ancient world
The Seven Wonders of the Ancient World, also known as the Seven Wonders of the World or simply the Seven Wonders, is a list of seven notable structures present during classical antiquity. The first known list of seven wonders dates back to the 2 ...
Seven Seas
The "Seven Seas" is a figurative term for all the seas of the known world. The phrase is used in reference to sailors and pirates in the arts and popular culture and can be associated with the Mediterranean Sea, the Arabian Seven Seas east of Af ...
Seven hills of Rome
The seven hills of Rome ( la, Septem colles/montes Romae, it, Sette colli di Roma ) east of the river Tiber form the geographical heart of Rome, within the walls of the city.
Hills
The seven hills are:
* Aventine Hill (Latin: ''Collis Aventi ...
and
Seven Kings of Rome
The king of Rome ( la, rex Romae) was the ruler of the Roman Kingdom. According to legend, the first king of Rome was Romulus, who founded the city in 753 BC upon the Palatine Hill. Seven legendary kings are said to have ruled Rome until 509 BC ...
Atlas
An atlas is a collection of maps; it is typically a bundle of maps of Earth or of a region of Earth.
Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geograp ...
also known as the
Pleiades
The Pleiades (), also known as The Seven Sisters, Messier 45 and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. At a distance ...
Religion and mythology
Judaism
The number seven forms a widespread typological pattern within
yom
Yom ( he, יום) is a Biblical Hebrew word which occurs in the Hebrew Bible. The word means day in both Modern and Biblical Hebrew.
Overview
Although ''yom'' is commonly rendered as day in English translations, the word yom can be used in differ ...
) of Creation, leading to the seventh day or Sabbath (Genesis 1)
*Seven-fold vengeance visited on upon Cain for the killing of
Abel
Abel ''Hábel''; ar, هابيل, Hābīl is a Biblical figure in the Book of Genesis within Abrahamic religions. He was the younger brother of Cain, and the younger son of Adam and Eve, the first couple in Biblical history. He was a shepherd ...
(Genesis 4:15)
*Seven pairs of every clean animal loaded onto the ark by Noah (Genesis 7:2)
*Seven years of plenty and seven years of famine in Pharaoh's dream (Genesis 41)
*Seventh son of Jacob, Gad, whose name means good luck (Genesis 46:16)
*Seven times bullock's blood is sprinkled before God (Leviticus 4:6)
*Seven nations God told the
Israelite
The Israelites (; , , ) were a group of Semitic-speaking tribes in the ancient Near East who, during the Iron Age, inhabited a part of Canaan.
The earliest recorded evidence of a people by the name of Israel appears in the Merneptah Stele o ...
s they would displace when they entered the land of
Israel
Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...
(Deuteronomy 7:1)
*Seven days of the Passover feast (Exodus 13:3–10)
*Seven-branched candelabrum or Menorah (Temple), Menorah (Exodus 25)
*Seven Shofar, trumpets played by seven priests for seven days to bring down the walls of Jericho (Joshua 6:8)
*Seven things that are detestable to God (Proverbs 6:16–19)
*Seven Pillars of the House of Wisdom (Proverbs 9:1)
*Seven archangels in the deuterocanonical Book of Tobit (12:15)
References to the number seven in Jewish knowledge and practice include:
*Seven divisions of the weekly readings or Torah reading, aliyah of the Torah
*Seven Jewish men (over the age of 13) called to read aliyahs in Shabbat morning services
*Seven blessings recited under the Jewish view of marriage, chuppah during a Jewish wedding ceremony
*Seven days of festive meals for a Jewish bride and groom after their wedding, known as Sheva Berachot or Seven Blessings
*Seven Sukkot#Prayers, Ushpizzin prayers to the Jewish patriarchs during the holiday of Sukkot
Christianity
Following the traditional of the Hebrew Bible, the New Testament likewise uses the number seven as part of a typological pattern:
*Seven loaves Feeding the multitude, multiplied into seven basketfuls of surplus (Matthew 15:32–37)
*Seven demons were driven out of Mary Magdalene (Luke 8:2)
*sayings of Jesus on the cross, Seven last sayings of Jesus on the cross
*Seven men of honest report, full of the Holy Ghost and wisdom (Acts 6:3)
*Seven Spirits of God, Seven churches of Asia, Seven Churches and Seven Seals in the Book of Revelation
References to the number seven in Christian knowledge and practice include:
*Seven Gifts of the Holy Spirit
*Works of Mercy, Seven Corporal Acts of Mercy and Works of Mercy, Seven Spiritual Acts of Mercy
*Seven deadly sins: lust, gluttony, greed, sloth, wrath, envy, and pride, and seven terraces of Mount Purgatory
*Seven Virtues: chastity, temperance, charity, diligence, kindness, patience, and humility
*Seven Joys of the Virgin, Seven Joys and Our Lady of Sorrows, Seven Sorrows of the Virgin Mary
*Seven Sleepers of Christian myth
*Seven Sacraments in the Catholic Church (though some traditions assign a different number)
Islam
References to the number seven in Islamic knowledge and practice include:
*Seven ayat in surat al-Fatiha, the first book of the holy Qur'an
*Seven Tawaf, circumambulations of Muslim pilgrims around the Kaaba in Mecca during the Hajj and the Umrah
*Seven walks between Al-Safa and Al-Marwah performed Muslim pilgrims during the Hajj and the Umrah
*Seven doors to hell (for heaven the number of doors is eight)
*Seventh day Naming ceremony#Islam, naming ceremony held for babies
*Seven enunciators of divine revelation (''nāṭiqs'') according to the celebrated Fatimid Caliphate, Fatimid Isma'ilism, Ismaili dignitary Nasir Khusraw
*Circle Seven Koran, the holy scripture of the Moorish Science Temple of America
Hinduism
References to the number seven in Hindu knowledge and practice include:
*Seven worlds in the universe and seven seas in the world in Hindu cosmology
*Seven sages or Saptarishi and their seven wives or Sapta Matrka in Hindu mythology
*Seven Chakras in eastern philosophy
*Seven stars in a constellation called "Saptarshi, Saptharishi Mandalam" in Indian astronomy
*Seven promises, or Saptapadi, and seven circumambulations around a fire at Hindu weddings
*Seven virgin goddesses or Saptha Kannimar Padal, Saptha Kannimar worshipped in temples in Tamil Nadu, India
*Seven hills at Tirumala known as Yedu Kondalavadu in Telugu language, Telugu, or ezhu malaiyan in Tamil language, Tamil, meaning "Sevenhills God"
*Seven steps taken by the Buddha at birth
*Seven divine ancestresses of humankind in Khasi people, Khasi mythology
*Seven octets or Saptak Swaras in Indian Music as the basis for Rāga, Ragas compositions
*Seven Social Sins listed by Mahatma Gandhi
Eastern tradition
Other references to the number seven in Eastern traditions include:
*Seven Lucky Gods or gods of good luck, fortune in Japanese mythology
*Seven-Branched Sword in Japanese mythology
*Seven Sages of the Bamboo Grove in China
*Seven minor symbols of yin and yang, yang in Taoist yin-yang
Other references
Other references to the number seven in traditions from around the world include:
*Seven palms in an Egyptian ''cubit, Sacred Cubit''
*Seven ranks in Mithraism
*Seven hills of Istanbul
*Seven islands of Atlantis
*Seven Cherokee clans
*Seven lives of cats in Iran and German language, German and Romance Languages, Romance language-speaking cultures
*Seven fingers on each hand, seven toes on each foot and seven pupils in each eye of the Irish epic hero Cúchulainn
*Seventh sons will be werewolf, werewolves in Galicia (Spain), Galician folklore, or the son of a woman and a werewolf in other European folklores
*Seventh son of a seventh son, Seventh sons of a seventh son will be magicians with special powers of healing and clairvoyance in some cultures, or vampires in others
*Seven prominent Guaraní mythology#Seven legendary monsters, legendary monsters in Guaraní mythology
*Seven gateways traversed by Inanna during her descent into the underworld
*''Seven Wise Masters'', a cycle of medieval stories
*Seven sister goddesses or fates in Baltic mythology called the List of Lithuanian gods and mythological figures#Gods and goddesses, Deivės Valdytojos.
*Seven legendary Cities of Gold, such as Quivira and Cíbola, Cibola, that the Spanish thought existed in South America
*Seven years spent by Thomas the Rhymer in the faerie kingdom in the eponymous British folk tale
*Seven-year cycle in which the Queen of Elphame, Queen of the Fairies pays a tithe to Hell (or possibly Hel (location), Hel) in the tale of Tam Lin
*''Seven Valleys'', a text by the Prophet-Founder Bahá'u'lláh in the Bahá'í faith
*Seven superuniverses in the cosmology of Urantia
*Seven psychological types called the Seven Rays in the teachings of Alice A. Bailey
*The sacred number of YemayaYemaya Santeria Church of the Orishas. Retrieved 25 November 2022
In culture
In literature
* Seven Dwarfs
* Seven features prominently in ''A Song of Ice and Fire'' by George R. R. Martin, namely, the Seven Kingdoms and the Faith of the Seven
In sports
* Sports with seven players per side
** Kabaddi
** Rugby sevens
** Water Polo
** Netball
** Handball
** Flag Football
** Ultimate Frisbee
* Seven is the least number of players a soccer team must have on the field in order for a match to start and continue.
* A touchdown plus an Conversion (gridiron football), extra point is worth seven points.
See also
*Diatonic scale (7 notes)
*Rainbow, Seven colors in the rainbow
*Seven continents
*Seven liberal arts
*Seven Wonders of the Ancient World
*Seven days of the Week
*Septenary, Septenary (numeral system)
*Year Seven (School)
*Se7en (disambiguation)
*Sevens (disambiguation)
*One-seventh area triangle
* Z with stroke (Ƶ)
*List of highways numbered 7
Notes
References
*Wells, D. ''The Penguin Dictionary of Curious and Interesting Numbers'' London: Penguin Group (1987): 70–71
{{DEFAULTSORT:7 (Number)
Integers
7 (number)