n.
Pronunciation: ' hwen, ' wen, (h)w ə n
Function: adverb
Etymology: Middle English, from Old English hwanne, hwenne; akin to Old High German hwanne when, Old English hw ā who ― more at WHO
Date: before 12th century
1 : at what time < when will you return>
2 a : at or during which time b : and then
3 : at a former and usually less prosperous time <brag fondly of having known him when ― Vance Packard>