what

1 what /ˈwɑːt/ /ˈwʌt/ pronoun
1 what
/ˈwɑːt/ /ˈwʌt/
pronoun
Britannica Dictionary definition of WHAT
1 
a  — used to ask for information about someone or something
b  — used to describe a question
2 
a  — used to ask someone to say something again because you have not clearly heard or understood it — often used to show surprise about the thing that someone has just said
b  informal — used to express surprise, excitement, etc.
3 
informal — used to ask what someone's last name is
4 
a  : that which : the one or ones that
b  : the kind that : the same as
c  : something that
d  : the thing or things that
— often followed by to + verb
◊ Guess what is often used to tell someone that you have surprising news.
e  : anything or everything that : whatever
5 
informal — used to direct attention to something that you are about to say

or what

informal
1 
— used to ask about what is happening, being done, etc.
2 
— used to ask if someone agrees with you

say what

— see 1say

what about

1 
a  : does that include (someone) : how about (someone)
b  : how does that affect (someone or something) : what should be done about (someone or something)
2 
— used to make a suggestion about what could be done
3 
— used to ask someone to tell you something in response to the thing that you have just said

what…for

: for what purpose or reason
— see also what for

what have you

informal
: any of the other things that might also be mentioned

what if

1 
: what would happen if
2 
: what does it matter if — used to say that something is not important
— see also so what at 3what

what of

1 
formal : how does that affect (someone or something) : what should be done about (someone or something)
2 
: why does (something) matter

what's it to you?

informal
: why do you want to know — used to respond in a somewhat angry or annoyed way to a question that you do not want to answer

what's more

: in addition : furthermore

what's up?

US, informal
— used as a friendly greeting

what's what

informal
: the true state of things : the things that need to be known or understood in order to make good judgments, decisions, etc.

what's with

informal or what's up with
1 
: what is the reason for (something)
2 
: what is wrong with (someone or something)
2 what /ˈwɑːt/ /ˈwʌt/ adjective
2 what
/ˈwɑːt/ /ˈwʌt/
adjective
Britannica Dictionary definition of WHAT
always used before a noun
1 
— used to ask someone to indicate the identity or nature of someone or something
2 
— used to say that someone or something is remarkable for having good or bad qualities
3 
— used to refer to an amount that someone has, uses, etc.
3 what /ˈwɑːt/ /ˈwʌt/ adverb
3 what
/ˈwɑːt/ /ˈwʌt/
adverb
Britannica Dictionary definition of WHAT
: in what way

so what

informal
— used to say that something said or done is not important

what with

— used to introduce the part of a sentence that indicates the cause of something