/ huː; NAmE / pronoun
used in questions to ask about the name, identity or function of one or more people :
Who is that woman?
I wonder who that letter was from.
Who are you phoning?
Who's the money for?
used to show which person or people you mean :
The people who called yesterday want to buy the house.
The people (who) we met in France have sent us a card.
used to give more information about sb :
Mrs Smith, who has a lot of teaching experience at junior level, will be joining the school in September.
And then Mary, who we had been talking about earlier, walked in.
- who am I, who are you, etc. to do sth?
- who's who
Old English hwā , of Germanic origin; related to Dutch wie and German wer .