Definition of since when
- "I'm a vegetarian." "Since when?"
- "You told me to do it." "Since when did you start listening to me?"
- Since when is it okay to cheat?
: from a definite past time until now
: before the present time : ago
: after a time in the past : subsequently
: at a time in the past after or later than : from the time in the past when
: in view of the fact that : because
: in the period after a specified time in the past : from a specified time in the past
What made you want to look up since when? Please tell us where you read or heard it (including the quote, if possible).