Epoch, in chronology (timekeeping), a point in time, such as 302 B.C. or October 30, 1936, or 7:34 A.M. Often the term is used in a more restricted sense, to mean a point in time at which an event occurred that was so striking or remarkable that it marks the beginning of a new era. For example, the birth of Jesus Christ is the epoch that marks the beginning of the Christian Era.