when

[ wen, hwen; unstressed wuhn, hwuhn ]

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

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.

3. at any time; whenever:

   He is impatient when he is kept waiting.

4. upon or after which; and then:

   We had just fallen asleep when the bell rang.

5. while on the contrary; considering that; whereas:

   Why are you here when you should be in school?

pronoun

1. what time:

   Till when is the store open?

2. which time:

   They left on Monday, since when we have heard nothing.

noun

1. the time of anything:

   the when and the where of an act.

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

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

Usage

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 History and Origins

Origin of when¹

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

Word History and Origins

Origin of when¹

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

Idioms and Phrases

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

Example Sentences

From the late ’60s until 1998, when the Good Friday Agreement wound down hostilities between the Catholic nationalist Irish Republican Army and the U.K.-supported loyalist protestant militias, Northern Ireland was afflicted with the conflict known as the Troubles.

From Los Angeles Times

Dolours asks, citing Gandhi and the Rev. Martin Luther King Jr., when her father mocks sit-ins and marches.

From Los Angeles Times

But the sisters are radicalized after being attacked in the 1969 Burntollet Bridge incident, when protesters calling for equal rights on a peaceful march from Belfast to Derry were ambushed by a mob wielding stones, iron bars and sticks spiked with nails.

From Los Angeles Times

At the same time, because it takes place over many years, with much elided, the series can sometimes feel abstract, especially when it moves away from Dolours — a history lesson in bits and pieces, rather than living history.

From Los Angeles Times

LeBron James, the tournament’s Most Valuable Player, said his thoughts Friday will be elsewhere when the Cup defense begins — and that’s the health of Spurs coach Gregg Popovich, who recently suffered a mild stroke.

From Los Angeles Times