What is the meaning of Epoch?

A particular period of history, or of a person's life, especially one considered noteworthy or remarkable.

A notable event which marks the beginning of such a period.

A specific instant in time, chosen as the point of reference or zero value of a system that involves identifying instants of time.

A geochronologic unit of hundreds of thousands to millions of years; a subdivision of a period, and subdivided into ages (or sometimes subepochs).

One complete presentation of the training data set to an iterative machine learning algorithm.

To divide (data) into segments by time period.

Source: wiktionary.org