Hopefully no one posted this yet (I skipped the middle page), but wikipedia says (in my neigborhood, all the restaurants call all of the below whatever they want):
A submarine sandwich (or just submarine where context would exclude the sea vessel, or even just sub) is any of various sandwiches made on a long roll (usually at least 12" long by 3 " wide) or baguette (called "French bread" or a "submarine roll" in the U.S.) , so called because of its shape. The contents typically include meat, cheese, lettuce, tomato, and various condiments, sauces or dressings.
The term is believed by some to have originated in a restaurant in Scollay Square in Boston, Massachusetts at the beginning of World War II. The sandwich was created to entice the large numbers of navy servicemen stationed at the Charlestown Navy Yard. The bread was a smaller specially baked baguette intended to be similar to the hull of the submarines it was named after.
Another legend suggests, the submarine sandwich was brought to the US by Dominic Conte, an Italian immigrant who came to New York in the early 1900s. He named the sandwich after a submarine hull he had seen on display. During World War II, the sandwiches were served by the thousands to soldiers at the submarine base in Groton, Connecticut which cemented the legend that the sandwiches originated in Groton.
Regional names and variations:
In the United States, the terms "submarine" and "sub" are widespread, but there are also many regional names for the sandwich, especially in the northeast part of the country:
Bomb New England, usually used for hot sandwiches with melted cheese & other toppings, such as a Steak bomb
Bomber New Jersey
Cosmo North Central Pennsylvania in and around Williamsport, PA - a cosmo is an oven toasted sub.
Grinder New England (some say this refers specifically to an oven-toasted sub) and Riverside, CA
Hero New York, northern New Jersey and the Eastern United States
Hoagie Philadelphia and environs, including South Jersey
Poor boy or Po' boy Gulf Coast, especially around New Orleans
Spuckie Boston, Massachusetts (now rare)
Torpedo New Jersey
Wedge Specific to some northeastern coastal sections of the Bronx, and the Long Island Sound shore towns of Westchester, New York, and Fairfield County, Connecticut, though definitely not universally recognized even in the region. Also in sections of northern New Jersey, adjacent Rockland County, and Putnam County in New York.
Zep (poss. trunc. of German zeppelin) New Jersey and Norristown, Pennsylvania
Italian Maine, where "Italian" is used regardless of the filling, which is specified separately, as a "ham Italian", "veggie Italian" or "roast beef Italian". A regular Italian is usually a ham Italian, made up of: ham, cheese, onions, olives, green peppers, pickles, and tomatoes. Italians are made to order at most convenience stores and gas stations. This term is also found in New Jersey.
An Italian sub, Italian combo, or Italian hoagie consists of Italian luncheon meats, typically capicola, prosciutto, and Genoa salami, with provolone, lettuce, tomato, oil, and vinegar. Thinly sliced pepperoni and bologna are sometimes added, and less expensive ham is often substituted for capicola and prosciutto.
A cheesesteak or steak and cheese is grilled sliced steak with melted cheese on a submarine roll. Common local variations include grilled onions, peppers, lettuce, tomato, ketchup or tomato sauce. The cheese is usually American, cheddar, provolone, or Cheez Whiz. Cheesesteaks are strongly associated with the Philadelphia area, while "steak and cheese" is more often heard elsewhere.
Submarine sandwiches are sold by delicatessens and a number of fast food restaurants and chains, including (listed by date opened); Jersey Mike's Subs (1956),Blimpie Subs (1964), Subway (1965), D'Angelo Sandwich Shops (1967), Mr. Sub (1968), Port of Subs (1972), Quiznos Subs (1981), Jimmy John's (1983), and Charley's Grilled Subs (1986). Submarines are especially popular in Pennsylvania.[citation needed] There are many "Mom and Pop" subs shops in the cities and boroughs of Pennsylvania.[citation needed] These sub shops are some of the most popular eateries in PennsylvaniaA small town will usually be the host of 2 or 3 sub shops.Larger cities have 2 or 3 sub shops per neighborhood.