epoch

noun

1. a period marked by distinctive character or reckoned from a fixed point or event

Similar word(s): era

Definition categories: time, period

2. (astronomy) an arbitrarily fixed date that is the point in time relative to which information (as coordinates of a celestial body) is recorded

Definition categories: time, date

3. a unit of geological time that is a subdivision of a period and is itself divided into ages

Definition categories: time

verb

1. (sciences, transitive) To divide (data) into segments by time period.