Definition of: period

(pir′ē·əd) noun
1. A definite portion of time marked and defined by some recurring event or phenomenon.
2. A lapse of time; a series of years; an age; era; also, a stage of life.
3. The concluding limit of any sequence of years, events, acts, or phenomena; termination.
4. The present day or time: with the.
5. Astron. The time of revolution of a heavenly body about its primary.
6. Med. A special phase or epoch distinguishable in the course of a disease: the period of augmentation; also, the menses.
7. A dot (.) placed on the line: used as a mark of rhetorical punctuation after every complete declarative sentence, after most abbreviations, as LL.D., pp.. after titles, headings, and sideheads, and often after Roman numerals. The same mark serves also as a decimal point.
8. A sentence in which completion of the sense is suspended till the close.
9. Geol. One of the divisions of geologic time, intermediate between the shorter epoch and the longer era: the Cretaceous period.
10. Music A group of measures arranged in two or more phrases and comprising a complete musical statement.
11. Math. a The interval between the equal recurring values of a dependent variable. b Any one of similar groups into which a number is divided, as when a root is to be extracted: in numeration or in recurring decimals. c The length of the smallest subinterval in the graph of the function of a real variable.
12. Physics The time that elapses between two successive similar phases of a vibration.
13. The completion or end of a cycle, event, or series of events.
14. Obs. A particular occasion or moment. See synonyms under END, TIME. [<OF periode <L periodus <Gk. periodos a going around, a rounded surface <peri- around + hodos a way]