lifetime

The word 'lifetime' is a transparent compound formed from two foundational Germanic nouns, 'life' and 'time'. Its logic is perfectly literal, directly combining the concept of animate existence ('life') with the concept of a measurable duration ('time'). This compound structure emerged in Middle English, reflecting a straightforward method of word formation where two independent, concrete terms are joined to specify a particular span—the time of one's life. The modern abstract meaning, extending to the duration of any entity's existence, retains this clear, compositional logic from its Old English roots.

Structure: life + time - life: From Old English 'līf' (life, existence), of Germanic origin. Functions as the core noun denoting existence. - time: From Old English 'tīma' (a period, season), of Germanic origin. Functions as a noun indicating a measured or measurable period.