noun

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 )
9. Gram., Rhetoric
   1. a sentence, esp. a balanced, well-constructed, complex sentence
   2. the natural pause in speaking used to indicate the end of a declarative sentence
   3. the mark of punctuation (.) used to indicate the end of a declarative sentence
   4. 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

Etymology: 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

adjective

interjection