ageyoudaoicibaDictYouDict[age 词源字典]
age: [13] Age has undergone considerable transmutations and abbreviations since its beginnings in Latin. Its immediate source in English is Old French aage, which was the product of a hypothetical Vulgar Latin form *aetāticum (the t is preserved in Provençal atge). This was based on Latin aetāt- (stem of aetās), which was a shortening of aevitās, which in turn came from aevum ‘lifetime’.

This entered English in more recognizable form in medieval, primeval, etc; it is related to Greek aión ‘age’, from which English gets aeon [17], and it can be traced back to the same root that produced (via Old Norse eí) the now archaic adverb ay(e) ‘ever’ (as in ‘will aye endure’).
=> aeon, aye[age etymology, age origin, 英语词源]
age (n.)youdaoicibaDictYouDict
late 13c., "long but indefinite period in human history," from Old French aage (11c., Modern French âge) "age; life, lifetime, lifespan; maturity," earlier edage, from Vulgar Latin *aetaticum (source of Spanish edad, Italian eta, Portuguese idade "age"), from Latin aetatem (nominative aetas), "period of life, age, lifetime, years," from aevum "lifetime, eternity, age," from PIE root *aiw- "vital force, life, long life, eternity" (see eon). Meaning "time something has lived, particular length or stage of life" is from early 14c. Used especially for "old age" since early 14c. Expelled native eld.
age (v.)youdaoicibaDictYouDict
"to grow old," late 14c., from age (n.). Meaning "to make old" is early 15c. Related: Aged; aging.