Definition
An imperative form used to request that the interlocutor indicate when one should stop doing something, esp. pouring a drink, because one has reached a sufficient amount.
In Context
- "Say when! ― When! Thanks."
- "The publican placed a whisky bottle and three glasses on the ledge and Grierson poured, with the courtesy of, "Say when," to the trooper, who was forced to exclaim, "Hold on!" in protest at a tumbler three-quarters full of whisky."