eternalyoudaoicibaDictYouDict[eternal 词源字典]
eternal: [14] Something that is eternal lasts literally for ‘aeons’. The word comes via Old French eternal from aeternālis, a late Latin development of the Latin adjective aeternus ‘eternal’. This in turn was a derivative of aevum ‘age’ (which crops up in English medieval, primeval, etc), a relative of Greek aión ‘age’ (from which English gets aeon) and archaic English aye ‘ever’.
=> aeon, aye, ever[eternal etymology, eternal origin, 英语词源]
eternal (adj.)youdaoicibaDictYouDict
late 14c., from Old French eternel "eternal," or directly from Late Latin aeternalis, from Latin aeternus "of an age, lasting, enduring, permanent, everlasting, endless," contraction of aeviternus "of great age," from aevum "age" (see eon). Used since Middle English both of things or conditions without beginning or end and things with a beginning only but no end. A parallel form, Middle English eterne, is from Old French eterne (cognate with Spanish eterno), directly from Latin aeternus. Related: Eternally. The Eternal (n.) for "God" is attested from 1580s.