| noun | an amount of time “a time period of 30 years” |
| noun | the interval taken to complete one cycle of a regularly repeating phenomenon |
| noun | (ice hockey) one of three divisions into which play is divided in hockey games |
| noun | a unit of geological time during which a system of rocks formed “ganoid fishes swarmed during the earlier geological periods” |
| noun | the end or completion of something “death put a period to his endeavors” |
| noun | the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause; ; --Hippocrates; --Aristotle “the women were sickly and subject to excessive menstruation” |
| noun | a punctuation mark (.) placed at the end of a declarative sentence to indicate a full stop or after abbreviations “in England they call a period a stop” |
| periodical | adjective | happening or recurring at regular intervals |
| menstruate | verb | undergo menstruation |
| catamenial | adjective | of or relating to menstruation or the menses |
| flow | verb | undergo menstruation |
| point | verb | mark (a psalm text) to indicate the points at which the music changes |