Other forms: epochs
An epoch is a long period marked off by some great event or change. A new epoch, the epoch of steam, mark an epoch.
It is formal, and in geology it is a precise unit: an epoch is a division of a period, so the Holocene epoch sits inside the Quaternary period. In astronomy and computing an epoch is a fixed reference moment from which time is counted — the Unix epoch is midnight on 1 January 1970. Note epoch-making, meaning important enough to start a new era, and that era is the everyday word for the same idea.
1nounepochA long period marked off by a great event.
“The invention began an epoch that lasted a century.”
synonyms: era, age
2nounfixedA fixed moment from which time is counted.
“Every timestamp is counted in seconds from that epoch.”
epoch is a period of time.
Greek epokhe meant a stopping point — the moment a star seems to pause at the top of its arc. An epoch was first the fixed instant you measure from, and only later the stretch of time after it, which is why astronomy still uses the older sense.
Proto-Indo-European
*seǵʰ-
Ancient Greek
ἐποχή — a check, cessation, stop, pause, epoch of a star, i.e., the point at which it seems to halt after reaching the highest, and generally the place of a star; hence, a historical epoch
Medieval Latin
epocha
English, today
epoch
Built from
From Medieval Latin epocha, from Ancient Greek ἐποχή (“a check, cessation, stop, pause, epoch of a star, i.e., the point at which it seems to halt after reaching the highest, and generally the place of a star; hence, a historical epoch”), from ἐπέχω (“to hold in, check”), from ἐπι- (“upon”) + ἔχω (“to have, hold”). a doublet of epoche.
Etymology from Wiktionary, CC BY-SA
Practised in History & Eras, Dinosaurs & Prehistory