Origins
The word 'age' entered English in the mid-thirteenth century from Old French 'aage' or 'eage,' which is the modern French 'âge.' The circumflex accent in modern French signals a lost 's' — but in this case, it actually signals a more dramatic contraction. The Old French form descends from Vulgar Latin '*aetāticum,' a suffixed form of Latin 'aetās' (genitive 'aetātis'), meaning 'age, lifetime, time of life, generation.' Latin 'aetās' is itself a contraction of the earlier 'aevitās,' from 'aevum,' meaning 'lifetime' or 'eternity.'
The PIE root behind all of this is *h₂eyw-, meaning 'vital force, lifetime, long life.' This root was remarkably productive across the Indo-European family, generating words that range in meaning from a single human lifespan to infinite eternity. Through Latin 'aevum,' it gave 'medieval' (from 'medium aevum,' literally 'the middle age'), 'primeval' (from 'primaevus,' 'of the first age'), and 'longevity' (from 'longaevitās,' 'long-agedness'). Through Latin 'aeternus' (contracted from 'aeviternus,' 'of lasting age'), it gave 'eternal' and 'eternity.'
Through Greek, the same root produced 'aiōn' (αἰών), meaning 'age, lifetime, era,' which entered English as 'aeon' or 'eon.' The Greek word also acquired a specialized theological sense in Gnostic Christianity, where 'aeons' were divine emanations or spiritual beings — a meaning that persists in philosophical and religious contexts. Gothic preserved the root as 'aiws' (time, eternity), and Old Norse had 'ævi' (lifetime).
Latin Roots
In English, 'age' has always carried both a concrete and an abstract sense. The concrete sense — how many years a person has lived — was primary from the beginning. The abstract sense — a period of history ('the Bronze Age,' 'the Ice Age,' 'the age of reason') — developed in the fourteenth century, influenced by Latin usage where 'aetās' could mean an era or generation. The phrase 'Middle Ages' (translating Latin 'medium aevum') entered English in the early nineteenth century.
The verb 'to age' appeared in the late fourteenth century, meaning to grow old. The adjective 'aged' has two pronunciations in standard English: one syllable (/eɪdʒd/) when used predicatively ('the wine has aged') and two syllables (/ˈeɪ.dʒɪd/) when used attributively before a noun ('an agèd man'). This double pronunciation is a survival from an earlier stage of English when past participle endings were more consistently syllabic.
The suffix '-age' in English (as in 'village,' 'passage,' 'marriage') is the same French suffix, from the same Vulgar Latin '-āticum,' but used productively to form abstract or collective nouns. It has no direct semantic connection to 'age' as a word, though both descend from the same Latin formation. The productivity of this suffix in English — creating words like 'shortage,' 'postage,' 'footage' — is one of the many legacies of the Norman French overlay on the English vocabulary.