A sandwich served on a long roll of bread, typically six inches to several feet in length, filled with a variety of ingredients including meat, cheese, and vegetables. Primarily heard in US. This restaurant across the road from our office makes the best sub sandwich in the city. I've gotten to where I go there two or three times a week for lunch. I'm ordering a few four-foot subs for the party this weekend, so if you have any food allergies, let me know before tomorrow.