- a rather large interval of time that is meaningful in the life of a person, in history, etc., because of its particular characteristics: a period of illness; a period of great profitability for a company; a period of social unrest in Germany.
- any specified division or portion of time: poetry of the period from 1603 to 1660.
- a round of time or series of years by which time is measured.
- a round of time marked by the recurrence of some phenomenon or occupied by some recurring process or action.
- the point of completion of a round of time or of the time during which something lasts or happens.
- Education. a specific length of time during school hours that a student spends in a classroom, laboratory, etc., or has free.
- any of the parts of equal length into which a game is divided.
- the time during which something runs its course.
- the present time.
- the point or character (.) used to mark the end of a declarative sentence, indicate an abbreviation, etc.; full stop.
- a full pause, as is made at the end of a complete sentence; full stop.
- a sentence, especially a well-balanced, impressive sentence: the stately periods of Churchill.
- a periodic sentence.
- an occurrence of menstruation.
- a time of the month during which menstruation occurs.
- Geology. the basic unit of geologic time, during which a standard rock system is formed: comprising two or more epochs and included with other periods in an era.
- Physics. the duration of one complete cycle of a wave or oscillation; the reciprocal of the frequency.
- Music. a division of a composition, usually a passage of eight or sixteen measures, complete or satisfactory in itself, commonly consisting of two or more contrasted or complementary phrases ending with a conclusive cadence; sentence(def 3).
- Also called period of rotation.the time in which a body rotates once on its axis.
- Also called period of revolution.the time in which a planet or satellite revolves once about its primary.
- Mathematics. See under periodic1(def 5).
- Classical Prosody. a group of two or more cola.
- noting, pertaining to, evocative of, imitating, or representing a historical period or the styles current during a specific period of history: period costumes; a period play.
- (used by a speaker or writer to indicate that a decision is irrevocable or that a point is no longer discussable): I forbid you to go, period.
Origin of period
- a portion of time of indefinable lengthhe spent a period away from home
- a portion of time specified in some waythe Arthurian period; Picasso's blue period
- (as modifier)period costume
- a nontechnical name for an occurrence of menstruation
- geology a unit of geological time during which a system of rocks is formedthe Jurassic period
- a division of time, esp of the academic day
- physics maths
- the time taken to complete one cycle of a regularly recurring phenomenon; the reciprocal of frequencySymbol: T
- an interval in which the values of a periodic function follow a certain pattern that is duplicated over successive intervalssin x = sin ( x + 2π ), where 2π is the period
- the time required by a body to make one complete rotation on its axis
- the time interval between two successive maxima or minima of light variation of a variable star
- chem one of the horizontal rows of elements in the periodic table. Each period starts with an alkali metal and ends with a rare gasCompare group (def. 11)
- Also called: full stop the punctuation mark (.) used at the end of a sentence that is not a question or exclamation, after abbreviations, etc
- a complete sentence, esp a complex one with several clauses
- Also called: sentence music a passage or division of a piece of music, usually consisting of two or more contrasting or complementary musical phrases and ending on a cadence
- (in classical prosody) a unit consisting of two or more cola
- rare a completion or end
Word Origin and History for period-revolution
early 15c., "course or extent of time," from Middle French periode (14c.) and directly from Medieval Latin periodus "recurring portion, cycle," from Latin periodus "a complete sentence," also "cycle of the Greek games," from Greek periodos "cycle, circuit, period of time," literally "a going around," from peri- "around" (see peri-) + hodos "a going, way, journey" (see cede).
Sense of "repeated cycle of events" led to that of "interval of time." Meaning "dot marking end of a sentence" first recorded c.1600, from similar use in Medieval Latin (in late 16c. English it meant "full pause at the end of a sentence"). Sense of "menstruation" dates from 1822. Educational sense of "portion of time set apart for a lesson" is from 1876. Sporting sense attested from 1898. As an adjective from 1905; period piece attested from 1911.
- An interval of time characterized by the occurrence of a certain condition, event, or phenomenon.
- One of the stages of a disease.
- A menstrual period.
- A sequence of elements arranged in order of increasing atomic number.
- A division of geologic time that is longer than an epoch and shorter than an era.
- The duration of one cycle of a regularly recurring action or event. See also cycle frequency.
- An occurrence of menstruation.
- In the Periodic Table, any of the seven horizontal rows that contain elements arranged in order of increasing atomic number. All the elements in a particular period have the same number of electron shells in their atoms, equal to the number of the period. Thus, atoms of nickel, copper, and zinc, in period four, each have four electron shells. See Periodic Table.