when

[hwen, wen; unstressed hwuh n, wuh n] /ʰwɛn, wɛn; unstressed ʰwən, wən/
adverb
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?
conjunction
3.
at what time:
to know when to be silent.
4.
at the time or in the event that:
when we were young; when the noise stops.
5.
at any time; whenever:
He is impatient when he is kept waiting.
6.
upon or after which; and then:
We had just fallen asleep when the bell rang.
7.
while on the contrary; considering that; whereas:
Why are you here when you should be in school?
pronoun
8.
what time:
Till when is the store open?
9.
which time:
They left on Monday, since when we have heard nothing.
noun
10.
the time of anything:
the when and the where of an act.
Origin
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
Can be confused
when, whence.
wen, when.

when's

[hwenz, wenz] /ʰwɛnz, wɛnz/
1.
contraction of when is:
When's the show over?
2.
contraction of when does:
When's the next train leave?
3.
contraction of when has:
When's he ever been an authority?
Usage note
See contraction.
Examples from the web for when
  • Correct tire inflation can only be obtained when weight of car is known.
  • when feelings of kinship transcend the species boundary.
  • when it comes to courtship, mankind has nothing on the animal kingdom.
  • Bonobos have an impressive vocabulary, especially when it comes to snacks.
  • Expect a line to form when you unveil this stunning dessert.
British Dictionary definitions for when

when

/wɛn/
adverb
1.
  1. at what time? over what period?: when is he due?
  2. (used in indirect questions): ask him when he's due
2.
say when, to state when an action is to be stopped or begun, as when someone is pouring a drink
3.
(subordinating) at a time at which; at the time at which; just as; after: I found it easily when I started to look seriously
4.
although: he drives when he might walk
5.
considering the fact that: how did you pass the exam when you'd not worked for it?
6.
at which (time); over which (period): an age when men were men
noun
7.
(usually pl) a question as to the time of some occurrence
Usage note
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
Word Origin
Old English hwanne, hwænne; related to Old High German hwanne, hwenne, Latin cum
Word Origin and History for when
adv.

Old English hwænne, hwenne, hwonne, from Germanic pronomial stem *khwa- (cf. Old Saxon hwan, Old Frisian hwenne, Middle Dutch wan, Old High German hwanne, German wann "when"), from PIE interrogative base *qwo- (see who).

Idioms and Phrases with when

when

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