From Late Latin 'aera' (an epoch), possibly from 'aes' (brass) — the counters used for calculation became a word for time.
A long and distinct period of history with a particular feature or characteristic; a system of chronology dating from a particular noteworthy event.
From Late Latin 'aera' (an epoch, a number used as a basis of calculation), possibly from Latin 'aera,' plural of 'aes' (genitive 'aeris,' brass, copper, money). The likeliest connection is that brass counters or tokens were used in accounting and calculation, and the word extended from 'counters' to 'a number used as a starting point for reckoning time.' The ultimate PIE root is *h2ey-es- (metal, copper, bronze), which also produced Latin 'aes' (bronze, money), Old
The word 'era' may ultimately derive from Latin 'aes' (brass, money), making it a cousin of the English word 'ore' (mineral-bearing rock). The connection is that brass counting tokens were used for arithmetic, and the 'era' was originally a number — a fixed starting point for calendar reckoning. Time, at the etymological root, was