but what, Informal. but that; but who; who or that … not: Who knows but what the sun may still shine.
    Say what? Slang. (used especially among teenagers) What's that you say? Would you repeat that?
    So what? Informal. (an expression of disinterest, disinclination, or contempt.)
    what for,
    1. why: What are you doing that for? You want that package now? What for?
    2. Older Use: Informal.a punishment or scolding: If he stays out late again, his parents are going to give him what for!
    what have you, other things of the same kind; so forth: money, jewels, stocks, and what have you.
    what if, what would be the outcome if; suppose that: What if everyone who was invited comes?
    what it takes, something that enables one to achieve success or attain a desired end, as good looks, ability, or money: There's a young woman who has what it takes to get along in the world.
    what's what, Informal. the true situation; all the facts: It's high time you told him what's what.

Origin of what

before 900; Middle English; Old English hwæt; cognate with German was, Dutch wat, Old Norse hvat; akin to Gothic hwa, Latin quod, Greek

Usage note

25. See doubt. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for what's what


British Dictionary definitions for what's what



  1. used with a noun in requesting further information about the identity or categorization of somethingwhat job does he do?
  2. (as pronoun)what is her address?
  3. (used in indirect questions)does he know what man did this?; tell me what he said
  1. the (person, thing, persons, or things) thatwe photographed what animals we could see
  2. (as pronoun)bring me what you've written; come what may
(intensifier; used in exclamations)what a good book!


in what respect? to what degree?what do you care?


not standard which, who, or that, when used as relative pronounsthis is the man what I saw in the park yesterday
what about what do you think, know, feel, etc, concerning?
what for
  1. for what purpose? why?
  2. informala punishment or reprimand (esp in the phrase give (a person) what for)
what have you someone, something, or somewhere unknown or unspecifiedcars, motorcycles, or what have you
what if
  1. what would happen if?
  2. what difference would it make if?
what matter what does it matter?
what's what informal the true or real state of affairs


informal don't you think? don't you agree?splendid party, what?

Word Origin for what

Old English hwæt; related to Old Frisian whet, Old High German hwaz (German was), Old Norse hvatr


The use of are in sentences such as what we need are more doctors is common, although many people think is should be used: what we need is more doctors
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for what's what



Old English hwæt, from Proto-Germanic *khwat (cf. Old Saxon hwat, Old Norse hvat, Danish hvad, Old Frisian hwet, Dutch wat, Old High German hwaz, German was, Gothic hva "what"), from PIE *qwod, neuter singular of *qwos "who" (see who).

Meaning "what did you say?" is recorded from c.1300; as an interrogative expletive at the end of sentences it is first recorded 1785, common early 20c. in affected British speech. Or what as an alternative end to a question is first attested 1766. "To give one what for is to respond to his remonstrant what for? by further assault" [Weekley]. The phrase is attested from 1873. What's-his-name for "unspecified person" is attested from 1690s; variant whatsisface is first recorded 1967. What's up? "what is happening?" first recorded 1881.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with what's what

what's what

see know what's what.


In addition to the idioms beginning with what

  • what about
  • what do you know
  • what do you take me for?
  • what for
  • what gives
  • what goes around comes around
  • what have you
  • what if
  • what in the world
  • what is more
  • what it takes
  • what makes one tick
  • what of it?
  • what the hell
  • what with

also see:

  • come what may
  • for all one is (what it's) worth
  • get what's coming to one
  • it's (what) a zoo
  • just what the doctor ordered
  • know the score (what's what)
  • left hand doesn't know what the right hand is doing
  • no matter (what)
  • on earth, what
  • or what?
  • practice what you preach
  • sauce for the goose is sauce for the gander, what's
  • so what
  • where's (what's) the beef?
  • you know something (you know what)
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.