sub

sub (http://definr.com/sub)

     n 1: 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 [syn: bomber,
          grinder, hero, hero sandwich, hoagie, hoagy, {Cuban
          sandwich}, Italian sandwich, poor boy, submarine,
          submarine sandwich, torpedo, wedge, zep]
     2: a submersible warship usually armed with torpedoes [syn: submarine,
         pigboat, U-boat]
     v : be a substitute [syn: substitute, stand in, fill in]