Period may refer to:

Common uses

Era An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth. Comp ...

, a length or span of time *

Full stop The full stop (Commonwealth English), period (North American English), or full point , is a punctuation mark. It is used for several purposes, most often to mark the end of a declarative sentence (as distinguished from a question or exclamation ...

(or period), a punctuation mark

Arts, entertainment, and media

Period (music) In music, the term period refers to certain types of recurrence in small-scale formal structure. In twentieth-century music scholarship, the term is usually used as defined by the ''Oxford Companion to Music'': "a period consists of two phrases ...

, a concept in musical composition *

Periodic sentence A periodic sentence is a sentence with a stylistic device featuring syntactical subordination to a single main idea, which usually is not complete until the very end of the sentence. The periodic sentence emphasizes its main idea by placing it at ...

(or rhetorical period), a concept in grammar and literary style. * Period, a descriptor for a historical or

period drama A historical drama (also period drama, costume drama, and period piece) is a work set in a past time period, usually used in the context of film and television. Historical drama includes historical fiction and romance film, romances, adventure f ...

* Period, a timeframe in which a particular style of

antique furniture A piece of antique furniture is a collectible interior furnishing of considerable age. Often the age, rarity, condition, utility, or other unique features make a piece of furniture desirable as a collectors' item, and thus termed an antique ...

or some other work of art was produced, such as the "Edwardian period" * ''

Period (Another American Lie) ''Period (Another American Lie)'' is the debut studio album by B.A.L.L., released in 1987 by Shimmy Disc. Track listing Personnel Adapted from the ''Period (Another American Lie)'' liner notes. ;B.A.L.L. * Don Fleming – vocals, g ...

'', a 1987 album by B.A.L.L. * ''Period'' (mixtape), a 2018 mixtape by City Girls * ''Period'', the final book in Dennis Cooper's George Miles cycle of novels

Mathematics

* In 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 ...

, the length of the repetend *

Period of a function A periodic function is a function that repeats its values at regular intervals. For example, the trigonometric functions, which repeat at intervals of 2\pi radians, are periodic functions. Periodic functions are used throughout science to desc ...

, length or duration after which a function repeats itself *

Period (algebraic geometry) In algebraic geometry, a period is a number that can be expressed as an integral of an algebraic function over an algebraic domain. Sums and products of periods remain periods, so the periods form a ring. Maxim Kontsevich and Don Zagier gav ...

, numbers that can be expressed as integrals of algebraic differential forms over algebraically defined domains, forming a ring

Science

Period (gene) Period (per) is a gene located on the X chromosome of ''Drosophila melanogaster''. Oscillations in levels of both ''per'' transcript and its corresponding protein PER have a period of approximately 24 hours and together play a central role in the ...

, a gene in ''Drosophila'' involved in regulating circadian rhythm *

Period (periodic table) A period in the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor. Arranged this way, elements ...

, a horizontal row of the periodic table * "Period-" or "per-iod-", in some chemical compounds, "per" refers to oxidation state, and "iod" refers to the compound containing

iodine Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...

Menstruation Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of hor ...

, also called a "period" *

Unit of time A unit of time is any particular time interval, used as a standard way of measuring or expressing duration. The base unit of time in the International System of Units (SI) and by extension most of the Western world, is the second, defined as a ...

or timeframe **

Period (geology) The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochrono ...

, a subdivision of geologic time **

Period (physics) Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

, the duration of time of one cycle in a repeating event **

Orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

, the time needed for one object to complete an orbit around another **

Rotation period The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...

, the time needed for one object to complete a revolution *

Wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...

, the spatial period of a periodic wave *

Sentence (linguistics) In linguistics and grammar, a sentence is a linguistic expression, such as the English example "The quick brown fox jumps over the lazy dog." In traditional grammar, it is typically defined as a string of words that expresses a complete thought, ...

, especially when discussing complex sentences in Latin syntax

Other uses

Period (school) A school period is a block of time allocated for lessons/classes in schools and colleges. They typically last between 30 and 120 minutes, with around 3-10 periods per school day. However, especially in higher education, there can be many more. Edu ...

, a class meeting time in schools *

Period (ice hockey) Ice hockey (or simply hockey) is a team sport played on ice skates, usually on an ice skating rink with lines and markings specific to the sport. It belongs to a family of sports called hockey. In ice hockey, two opposing teams use ice hock ...

, a division of play in an ice hockey game *

Accounting period An accounting period, in bookkeeping, is the period with reference to which management accounts and financial statements are prepared. In management accounting the accounting period varies widely and is determined by management. Monthly account ...

, often shortened to "period" in business, an accounting timeframe analogous to a month

Common uses

Arts, entertainment, and media

Mathematics

Science

Other uses

See also