Etymology: Middle English, from Old English hwā; akin to Old High German hwer, interrogative pronoun, who, Latin quis, Greek tis, Latin qui, relative pronoun, who
Date: before 12th century
1. what or which person or persons — used as an interrogative <who was elected?> <find out who they are> — used by speakers on all educational levels and by many reputable writers, though disapproved by some grammarians, as the object of a verb or a following preposition <who did I see but a Spanish lady — Padraic Colum> <do not know who the message is from — G. K. Chesterton> 2. the person or persons that ; whoever 3. — used as a function word to introduce a relative clause; used especially in reference to persons <my father, who was a lawyer> but also in reference to groups <a generation who had known nothing but war — R. B. West> or to animals <dogs who…fawn all over tramps — Nigel Balchin> or to inanimate objects especially with the implication that the reference is really to a person <earlier sources who maintain a Davidic ancestry — F. M. Cross> — used by speakers on all educational levels and by many reputable writers, though disapproved by some grammarians, as the object of a verb or a following preposition <a character who we are meant to pity — Times Literary Supplement> Usage: see whom, that
New Collegiate Dictionary. 2001.