period

An interval of time characterized by the occurrence of a certain condition, event, or phenomenon.

An interval of time characterized by the prevalence of a specified culture, ideology, or technology.

An interval regarded as a distinct evolutionary or developmental phase.

A unit of time, longer than an epoch and shorter than an era.

Any of various arbitrary units of time, especially.

Any of the divisions of the academic day.

A division of the playing time of a game.

The time interval between two successive occurrences of a recurrent event or phases of an event; a cycle.

A point or portion of time at which something is ended; a completion or conclusion.