[hwen, wen; unstressed hwuh
n, wuhn] 
| 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? |
| 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? |
| 8. | what time: Till when is the store open? |
| 9. | which time: They left on Monday, since when we have heard nothing. |
| 10. | the time of anything: the when and the where of an act. |
[hwenz, wenz] | 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? |
| when (hwěn, wěn) adv. At what time: When will we leave? conj.
n. The time or date: Have they decided the where and when? [Middle English, from Old English hwenne; see kwo- in Indo-European roots.] Usage Note: In informal style when is often used after forms of be in definitions: A dilemma is when you don't know which way to turn. Although useful, this construction is widely regarded as incorrect or unsuitable for formal discourse. In formal style such definitions should be recast to eliminate is when, either by supplying generic term that may be modified by a restrictive adjective clause (A dilemma is a situation in which you don't know which way to turn) or by making the when-clause adverbial (You are in a dilemma when you don't know which way to turn). |
when
In addition to the idioms beginning with when, also see cross a bridge when one comes to it; push comes to shove, when.