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Epoch

/ˈɛpək/noun

A period of history, or the fixed date from which such a period is measured.

The Greek roots

ἐπί
epí
upon
+
ἔχω
ékhō
to hold

Literally: a holding back

The story of the word

The astronomer's sense is the original and the strict one: an epoch is not a stretch of time but the instant chosen as its origin, the moment for which a star's coordinates are stated, J2000.0 for example. English loosened it into an age. The Greek noun had a second career among the Skeptics, where ἐποχή is suspension of judgement, the deliberate refusal to assent, a use Husserl revived for phenomenology.

How it travelled
Ancient Greek → Modern Latin → English
First recorded
1610s

Same family

epidemicepilogueschemehectic

In a sentence

Positions are given for epoch J2000.0 and drift slowly afterwards.

The fall of the wall closed one epoch and opened another.

Built on the same root

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