WHO

(ASKING) [pronoun] - used esp. in questions as the subject or object of a verb, when asking which person or people, or when asking what someone's name isWho did this?Who's she?Who are all those people?Hi, I'm Liz - who are you?She asked me if I knew who had got the job.Who (also formal whom) do you want to talk to?I don't know who (also formal whom) to ask to the party.Who can also be used with verbs relating to knowing, when you want to say that something is not known."Are they going to get married?" "Who knows?" (= It is not possible to know at the moment.)Who can tell why they killed themselves? (= No one can know the real reason.)To know who's who is to know the name and position of each person, esp. in an organization.Who's Who is a book containing information about the world's richest or most famous people. A who's who is any list of the main people in a particular group.Who's Who states he retired in 1980.The guest list reads like a who's who of top American businessmen.