(idiomatic, colloquial) Informal greeting roughly equivalent to How are you? or How's it going?

how much does it cost?

(idiomatic, informal) Why; why is it; for what reason or purpose; due to what cause?

Used to inquire about the weather. / (by extension, idiomatic) Indicating a change of subject to unimportant topics.

(nonstandard) Standing for an unknown or queried ordinal number.

Used to ask someone to repeat something

Used literally: what length. / Used literally: what duration.

Used literally: for what duration.

(UK dialect, West Country and West Midlands, informal) How are you? (greeting)

(rhetorical question) A general statement of surprise or bemusement with regard to a particular event.; isn't that good, or unexpected, etc.