who

1. (interrogative) What person or people; which person or people; asks for the identity of someone; used in a direct or indirect question.Examples: "You're getting married‽ Who to? (direct question)"; "I don't know who it is. (indirect question)"; "Ia[go]. Hee’s married. Caſ[ſio]. To who? […] Ia[go]. Marry to. ---- Come Captaine, will you goe? Oth[ello]. Ha, with who?"interrogativenominativepluralsingular

2. (relative) Introduces a relative clause having a human antecedent.Examples: "That's the man who works at the newsagent. (defining)"; "My sister, who works in the accounts department, just got promoted to manager. (non-defining)"; "Chorban: I don't really think my scanning disturbs them, but the authorities might disagree. Chorban: I'd like to do it more openly, but it's not really worth getting arrested over. Shepard: I could help you out. I'm not worried about the authorities. Chorban: I don't even know who you are."nominativepluralrelativesingular

3. (relative) Introduces a relative clause having a human antecedent.Examples: "That's the man who I saw earlier."; "My brother, who you met the other day, is coming to stay for the weekend."nominativepluralrelativesingular

4. (fused relative, archaic or marginal) Whoever, he who, they who.Examples: "Who insults my mother insults me."; "Give it to who deserves it."; "Who steals my purse steals trash."nominativepluralsingular

5. (informal, especially non-US) Also used with names of collective nouns that are groups of people, especially singularly-named musical groups or sports teams.Examples: "Who are the Miami Heat?"informalnominativepluralsingular