period

period [pir′ē əd]

n.

[ME paryode < MFr periode < L periodus < Gr periodos, a going around, cycle < peri-, around + hodos, way < IE base * sed-, to go > Sans ā-sad-, go toward]

1. the interval between recurrent astronomical events, as between two full moons

2. the interval between certain happenings [a ten-year period of peace]

3. a portion of time, often indefinite, characterized by certain events, processes, conditions, etc.; stage [a period of change, the present period]

4. any of the portions of time into which an event of fixed duration, as a game or a school day, is divided

5. the full course, or one of the stages, of a disease

6. an occurrence of menstruation; menses

7. an end, completion, or conclusion, or a point of time marking this [death put a period to his plans]

8. Geol. a subdivision of an era in geologic time corresponding to the rock strata of a SYSTEM (sense 10): see the geologic time chart in the Reference Supplement

9. Gram. Rhetoric

a) a sentence, esp. a balanced, well-constructed, complex sentence

b) the natural pause in speaking used to indicate the end of a declarative sentence

c) the mark of punctuation (.) used to indicate the end of a declarative sentence

d) the dot (.) following many abbreviations

10. Math. the interval from one repetition to the next of a recurrent or self-duplicating function

11. Music a group of two or more related phrases ending with a cadence

12. Physics the interval of time necessary for a regularly recurring motion to make a complete cycle

13. Prosody a rhythm group of two or more cola in the Greek system

adj.

of or like that of an earlier period or age [period furniture]

interj.

Informal used to indicate that the preceding statement is the speaker's last, conclusive, word on the subject [be home by midnight or you're grounded, period!]

SYN.- PERIOD is the general term for any portion of time; EPOCH and ERA are often used interchangeably, but in strict discrimination EPOCH applies to the beginning of a new period marked by radical changes, new developments, etc. and ERA, to the entire period [the steam engine marked an epoch in transportation, an era of revolution ]; AGE is applied to a period identified with some dominant personality or distinctive characteristic [the Stone Age]; EON refers to an indefinitely long period [it all happened eons ago ]