A length of time. • A length of time in history seen as a single coherent entity; an epoch, era. • The punctuation mark “.” (indicating the ending of a sentence or marking an abbreviation). • A decisive end to something; a stop. • The length of time during which the same characteristics of a periodic phenomenon recur, such as the repetition of a wave or the rotation of a planet. • Female menstruation; an episode of this. • The set of symptoms associated with menstruation, even if not accompanied by menstruation; an episode of these symptoms. • A section of an artist's, writer's (etc.) career distinguished by a given quality, preoccupation etc. • Each of the divisions into which a school day is split, allocated to a given subject or activity. • Each of the intervals, typically three, of which a game is divided. • One or more additional intervals to decide a tied game, an overtime period. • The length of time for a disease to run its course. • An end or conclusion; the final point of a process, a state, an event, etc. • A complete sentence, especially one expressing a single thought or making a balanced, rhythmic whole. • A specific moment during a given process; a point, a stage. • A row in the periodic table of the elements. • A geochronologic unit of millions to tens of millions of years; a subdivision of an era, and subdivided into epochs. • A Drosophila gene, the gene product of which is involved in regulation of the circadian rhythm. • Two phrases (an antecedent and a consequent phrase). • The length of an interval over which a periodic function, periodic sequence or repeating decimal repeats; often the least such length.