Whats the difference between chowder and soup?
All chowders (pronounced "sh-owe-dare" if you want to annoy French waiters; one of my favorite pastimes) are soup, but not all soups are chowders.
Originally, the term referred to any thick base seafood soup, but now you can make just about anything into a chowder. Chowders are always somewhat thick in viscosity and opaque; this usually results from the inclusion of flour, though some thicken their "sh-owe-dare" with heavy cream (my mom did this, and it was killer).
The most common chowders are of course clam (New England or Manhattan style) and corn, but I’ve had crab chowder that would knock you socks off. As stated earlier, you can make just about any soup a chowder by adding salt or heavy cream and calling it chowder, but if you ever eat in a restaurant that advertises liver and Brussels sprouts chowder, you should light yourself on fire and run screaming out of there.