Pronunciation: (nīt'kap"),[key] —n. 1. Informal.an alcoholic drink taken at bedtime or at the end of a festive evening.
2. a cap for the head, intended primarily to be worn in bed.
3. Sports Informal.the last event of the program for the day, esp. the second game of a doubleheader in baseball or the last race of the day in horse racing.