epochs

'epochs'

[era.n.01] as in: a period marked by distinctive character or reckoned from a fixed point or event

'epochs'

[epoch.n.02] as in: (astronomy) an arbitrarily fixed date that is the point in time relative to which information (as coordinates of a celestial body) is recorded

'epochs'

[epoch.n.03] as in: a unit of geological time that is a subdivision of a period and is itself divided into ages