[ wen, hwen; unstressed wuhn, hwuhn ]
See synonyms for when on Thesaurus.com
  1. at what time or period? how long ago? how soon?: When are they to arrive?When did the Roman Empire exist?

  2. under what circumstances? upon what occasion?: When is a letter of condolence in order?When did you ever see such a crowd?

  1. at what time: to know when to be silent.

  2. at the time or in the event that: when we were young;when the noise stops.

  1. at any time; whenever: He is impatient when he is kept waiting.

  2. upon or after which; and then: We had just fallen asleep when the bell rang.

  3. while on the contrary; considering that; whereas: Why are you here when you should be in school?

  1. what time: Till when is the store open?

  2. which time: They left on Monday, since when we have heard nothing.

  1. the time of anything: the when and the where of an act.

Origin of when

First recorded before 1000; Middle English when(ne), Old English hwenne; cognate with German wann “when,” wenn “if, when” (compare Gothic hwan “when, how”); akin to who, what

Words that may be confused with when

Words Nearby when

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use when in a sentence

  • They take their coats off anywhere and any-when, and somehow it strikes the visitor as the most symbolic thing about them.

    Letters from America | Rupert Brooke
  • "But all that seems such a pity-when they've tried," grieved Billy.

    Miss Billy's Decision | Eleanor H. Porter
  • "Some actor fellow once said w-when you w-went West you were c-camping out," chattered Carley.

British Dictionary definitions for when


/ (wɛn) /

    • at what time? over what period?: when is he due?

    • (used in indirect questions): ask him when he's due

  1. say when to state when an action is to be stopped or begun, as when someone is pouring a drink

  1. (subordinating) at a time at which; at the time at which; just as; after: I found it easily when I started to look seriously

  2. although: he drives when he might walk

  3. considering the fact that: how did you pass the exam when you'd not worked for it?

  4. at which (time); over which (period): an age when men were men

  1. (usually plural) a question as to the time of some occurrence

Origin of when

Old English hwanne, hwænne; related to Old High German hwanne, hwenne, Latin cum

usage For when

When should not be used loosely as a substitute for in which after a noun which does not refer to a period of time: paralysis is a condition in which (not when) parts of the body cannot be moved

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

Other Idioms and Phrases with when


In addition to the idioms beginning with when

  • when all's said and done
  • when in Rome do as the Romans do
  • when it comes to
  • when least expected
  • when one's back is turned
  • when one's ship comes in
  • when pigs fly
  • when the cat's away, the mice will play
  • when the chips are down
  • when the dust has settled
  • when the going gets tough, the tough get going
  • when the shit hits the fan

also see:

  • cross a bridge when one comes to it
  • push comes to shove, when

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.