—interrog.adj.
1 asking for a choice from an indefinite number or for a statement of amount, number, or kind (what books have you read?; what news have you?).
2 colloq. = WHICH interrog.adj. (what book have you chosen?).
—adj. (usu. in exclam.) how great or remarkable (what luck!).
—rel.adj. the or any ... that (will give you what help I can).
—pron. (corresp. to the functions of the adj.)
1 what thing or things? (what is your name?; I don't know what you mean).
2 (asking for a remark to be repeated) = what did you say? 3 asking for confirmation or agreement of something not completely understood (you did what?; what, you really mean it?).
4 how much (what you must have suffered!).
5 (as rel.pron.) that or those which; a or the or any thing which (what followed was worse; tell me what you think).
—adv. to what extent (what does it matter?).
Phrases and idioms:
what about what is the news or position or your opinion of (what about me?; what about a game of tennis?). what-d'you-call-it (or what's-its-name) a substitute for a name not recalled. what ever what at all or in any way (what ever do you mean?) (see also WHATEVER). what for colloq.
1 for what reason? 2 a severe reprimand (esp. give a person what for). what have you colloq. (prec. by or) anything else similar.
what if?
1 what would result etc. if.
2 what would it matter if. what is more and as an additional point; moreover. what next? colloq. what more absurd, shocking, or surprising thing is possible? what not (prec. by and) other similar things. what of? what is the news concerning? what of it? why should that be considered significant? what's-his (or -its) -name = what-d'you-call-it. what's what colloq. what is useful or important etc. what with colloq. because of (usu. several things).
Etymology: OE hwaeligt f. Gmc
Useful english dictionary. 2012.