Also found in: Thesaurus, Medical, Idioms, Encyclopedia, Wikipedia.
1. Nautical A submarine.
2. A submarine sandwich.
sub 2(sŭb) Informal
v. subbed, sub·bing, subs
To act as a substitute: a graduate student subbing for the professor.
1. To put or use (a person or thing) as a substitute: The coach subbed fresh players toward the end of the game. The cook subbed oil for butter.
2. Usage Problem To replace; substitute: The player was subbed after she committed two errors. Sub the chicken with tofu to make the dish vegetarian. See Usage Note at substitute.