Some places interchange the word, but when people say:
Dressing - usually southern/southern roots, its cornbread based and baked in its own pan, usually includes eggs as part of the binding agent/liquid, dense
Stuffing - more of a northern word, usually uses bread cubes, can either go inside the turkey (although Ive read conflicting things about the safety of this) or baked on the side, usually just uses broth - no egg, fluffier and loser