A submarine sandwich, also known as a sub, hoagie, hero, or grinder, is a
type of sandwich made from a cylindrical bread roll split lengthwise and
filled with meats, cheeses, vegetables, and condiments.
It has many different names.

Hoagie, a submarine sandwich filled with Italian meats, cheeses, and other
toppings. The name likely comes from the Philadelphia area where, during
World War I, Italian immigrants who worked at the Hog Island shipyard
began making sandwiches; they were originally called “hoggies”
before the name hoagie took hold.