eternal

the word 'eternal' entered english in the 14th century from the old french 'eternel', which itself evolved from the late latin 'aeternalis'. this latin adjective was formed from the classical latin noun 'aeternum', meaning 'eternity', a derivative of 'aevum' meaning 'age' or 'lifetime'. the ultimate origin traces back to the proto-indo-european root h₂eyu- or h₂eyw-, meaning 'vital force' or 'long life', which also gave rise to greek 'aiōn' (age, eternity) and sanskrit 'āyuḥ' (life). the semantic journey moved from the concrete concept of a 'lifetime' to the abstract, boundless concept of 'everlasting time', capturing the idea of existence beyond the limits of a single age.

the word 'eternal' is a simplex form derived from a single latin root. it is not productively segmented into smaller, meaningful morphemes in modern english spelling.