Main entry: submarine, sub, U-boat, pigboat
Definition: a submersible warship usually armed with torpedoes
Main entry: poor boy, submarine, submarine sandwich, torpedo, sub, Cuban sandwich, grinder, hero, hero sandwich, hoagie, hoagy, wedge, zep, bomber, Italian sandwich
Definition: a large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States
Main entry: substitute, sub, fill in, stand in
Definition: be a substitute
Usage: The young teacher had to substitute for the sick colleague; The skim milk substitutes for cream--we are on a strict diet