Meaning

noun a number that has no factor but itself and 1

noun the period of greatest prosperity or productivity

noun the second canonical hour; about 6 a.m.

originFrom Middle English prime, from Old French prime and its etymon, Latin prīmus (“first”), from earlier prīsmos < *prīsemos < Proto-Italic *priisemos, ultimately from Proto-Indo-European *per- (“beyond, before”). Doublet of primo and primus. The noun sense "apostrophe-like symbol" originates from the fact that the symbol ′ was originally a superscript Roman numeral one.

Etymology from Wiktionary, CC BY-SA 3.0