primeyoudaoicibaDictYouDict[prime 词源字典]
prime: [OE] Latin prīmus ‘first’ came from an earlier *prīsmo-, which went back ultimately to Indo-European *pro ‘before, in front’ (ancestor also of English first). English first acquired it direct from Latin in the Anglo-Saxon period as an ecclesiastical term for the earliest of the canonical hours, and this is the source of the modern English noun uses of the word (as in ‘in one’s prime’).

The adjective prime was borrowed in the 14th century from Old French prime. English has a wide range of words that go back to derivatives of Latin prīmus, including premier [15], prim, primal [17], primary [15], primate [13], primitive [14], prince, principal, and principle. The trade-name Primus was first used for a sort of paraffin lamp in the early years of the 20th century.
=> first, premier, prim, primitive, prince, principle[prime etymology, prime origin, 英语词源]
prime (adj.)youdaoicibaDictYouDict
late 14c., "first in order," from Latin primus "first, the first, first part," figuratively "chief, principal; excellent, distinguished, noble" (source also of Italian and Spanish primo), from pre-Italic *prismos, superlative of PIE *preis- "before," from root *per- (1) "beyond, through" (see per).

Meaning "first in importance" is from 1610s in English; that of "first-rate" is from 1620s. Arithmetical sense (as in prime number) is from 1560s; prime meridian is from 1878. Prime time originally (c. 1500) meant "spring time;" broadcasting sense of "peak tuning-in period" is attested from 1961.
prime (n.)youdaoicibaDictYouDict
"earliest canonical hour" (6 a.m.), Old English prim, from Medieval Latin prima "the first service," from Latin prima hora "the first hour" (of the Roman day). Meaning "most vigorous stage" first recorded 1530s; specifically "springtime of human life" (often meaning ages roughly 21 to 28) is from 1590s. In classical Latin, noun uses of the adjective meant "first part, beginning; leading place."
prime (v.)youdaoicibaDictYouDict
"to fill, charge, load" (a weapon), 1510s, probably from prime (adj.). Meaning "to cover with a first coat of paint or dye" is from c. 1600. To prime a pump (c. 1840) meant to pour water down the tube, which saturated the sucking mechanism and made it draw up water more readily. Related: Primed; priming.