This is as good an explanation as I have seenDo you know why they are poboy's?
A po' boy (also po-boy, po boy, or poor boy) is a traditional sandwich from Louisiana. It almost always consists of meat, usually roast beef, or fried seafood (shrimp, oysters, crawfish or fish). Served on baguette-like New Orleans French bread, known for its crisp crust and fluffy center. Po-boys come dressed with mayo, lettuce, tomato & pickle.
A submarine sandwich, also known as a sub, wedge, hoagie, hero, grinder, baguette, or one of many regional naming variations, is a sandwich that consists of a long roll of Italian or French bread, split widthwise either into two pieces or opened in a "V" on one side, and filled with a variety of meats, cheeses, vegetables, seasonings, and sauces.