The verb 'wean' originates from the Old English 'wenian', meaning "to accustom, habituate," which is itself derived from the Proto-Germanic 'wanjan'. This root connects to the broader Proto-Indo-European base 'wen-', associated with desire or striving, reflecting the process of guiding a child's desire from one source of nourishment to another. The specific application to transitioning an infant from breast milk to other food became the primary sense in Middle English. The '-ed' suffix is the standard Germanic marker for the past tense and past participle, completing the word's form to describe the completed action of this accustoming process.

Structure: wean (to accustom) + ed (past tense suffix) wean (Old English, meaning to accustom, especially to food other than mother's milk); ed (Old English, suffix forming the past tense and past participle of weak verbs).