Pronunciation: (pēr'ē-ud),[key] —n. 1. 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. 2. any specified division or portion of time: poetry of the period from 1603 to 1660. 3. a round of time or series of years by which time is measured.
4. a round of time marked by the recurrence of some phenomenon or occupied by some recurring process or action.
5. the point of completion of a round of time or of the time during which something lasts or happens.
6. Educ.a specific length of time during school hours that a student spends in a classroom, laboratory, etc., or has free.
7. any of the parts of equal length into which a game is divided.
8. the time during which something runs its course.
9. the present time.
10. the point or character (.) used to mark the end of a declarative sentence, indicate an abbreviation, etc.; full stop.
11. a full pause, as is made at the end of a complete sentence; full stop.
12. a sentence, esp. a well-balanced, impressive sentence: the stately periods of Churchill. 13. a periodic sentence.
14. an occurrence of menstruation.
15. a time of the month during which menstruation occurs.
16. Geol.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. See table under geologic time. 17. Physics.the duration of one complete cycle of a wave or oscillation; the reciprocal of the frequency.
18. 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.
19. Astron. a. Also called period of rotation. the time in which a body rotates once on its axis.
b. Also called period of revolution. the time in which a planet or satellite revolves once about its primary.
20. Math.See under periodic (def. 5).
21. Class. Pros.a group of two or more cola.
—adj. 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.
—interj. (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.