what

Concise Oxford English Dictionary © 2008 Oxford University Press:
what/wɒt/

▶pronoun & determiner

• 1 asking for information specifying something.

  ■ [as pron.] asking for repetition of something not heard or confirmation of something not understood.

• 2 [as pron.] the thing or things that.

• 3 whatever.

• 4 used to emphasize something surprising or remarkable.

▶interrogative adverb

• 1 to what extent?

• 2 informal, dated used for emphasis or to invite agreement: poor show, what?

– phrases
and (or or) what have you informal and/or anything else similar.
and what not informal and other similar things.
what about ——?

• 1 used when asking for information or an opinion.

• 2 used to make a suggestion.

what-d'you-call-it (or what's-its-name) informal used as a substitute for a name not recalled.
what for? informal for what reason?
what if ——?

• 1 what would result if ——?

• 2 what does it matter if ——?

what is more and as an additional point; moreover.
what of ——? what is the news concerning ——?
what of it? why should that be considered significant?
what's-his (or -its) -name another term for what-d'you-call-it .
what's what informal what is useful or important.
what with because of.

– origin OE hwæt, of Gmc origin.