1when 
/ˈwɛn/ adverb
/ˈwɛn/ adverb 1 : at what time
▪ When will you return? ▪ When did the American Civil War begin? ▪ The detective asked me when I last saw her. ▪ When is the next performance? ▪ (Do you) remember when that happened? 2 a : at, in, or during which
▪ It was a time when people didn't have to lock their doors. ▪ the happy days when we were together
b : at or during which time
▪ We're still waiting for the test results, when we'll decide our next move. 3 informal : at a former and usually less successful time
▪ I can say I knew you when. [=I knew you before you were famous or successful]
▪ When will you return? ▪ When did the American Civil War begin? ▪ The detective asked me when I last saw her. ▪ When is the next performance? ▪ (Do you) remember when that happened?
▪ It was a time when people didn't have to lock their doors. ▪ the happy days when we were together
b : at or during which time
▪ We're still waiting for the test results, when we'll decide our next move.
▪ I can say I knew you when. [=I knew you before you were famous or successful]
