pronoun

1. the nature, class, name, purpose, etc. of a thing what is that object?what is your address?
   1. an explanation or repetition of something previously said you told them what?
   2. such an explanation or repetition: used elliptically “Sh. Quiet!”“What?”
   a quantity, sum, etc. what will it cost? the value, importance, or effect of something what is life without music?
2. that which or those which to know what one wants anything that do what you will the exact person or thing that he's not what he was five years ago that or who: a nonstandard usage the man what gave it to me
4. Chiefly Brit., Informal used to end a sentence with a general or rhetorical interrogative force it's rather late, what? used to introduce a parenthetical element in a sentence she has, what is rare, true tolerance used elliptically to mean “what it is,” “what to do,” etc. I'll tell you what!

Etymology: ME hwat < OE hwæt, neut. of hwa, who < IE interrogative base *kwo-, *kwe- > where, who, L qui, who what, Lith kàs, what, who

noun

adjective

1. which or which kind of: used interrogatively or relatively in asking for or specifying the nature, identity, etc. of a person or thing what man told you that? he knows what role she played
2. as much, or as many, as take what time (or men) you need
3. how great, surprising, magnificent, disappointing, etc.: in exclamations what a man! what nonsense!

adverb

1. in what respect? to what degree? how? what does it matter?
2. how greatly, surprisingly, etc.: in exclamations what tragic news!
3. Obsolete why?

conjunction

interjection