Old English wenian "to accustom," from Proto-Germanic *wanjanan (cf. Old Norse venja, Dutch wennen, Old High German giwennan, German gewöhnen "to accustom"), from *wanaz "accustomed" (related to wont). The sense of weaning a child from the breast in Old English was generally expressed by gewenian or awenian, which has a sense of "unaccustom" (cf. German abgewöhnen, entwöhnen "to wean," literally "to unaccustom"). The prefix subsequently wore off. Figurative extension to any pursuit or habit is from 1520s.
v. weaned, wean·ing, weans
To deprive permanently of breast milk and begin to nourish with other food.
To accustom the young of a mammal to take nourishment other than by suckling.
To gradually withdraw from a life-support system.