In the movies: What is the difference between an Orc and a Goblin?

Hi,well,4rm what i know,orcs were elves turned bad, who got corrupted by evil,mostly by sauron and and the evil valaar(i dont remember his name now). And goblins are..just creatures,like dwarves,humans,elves etc etc.And in the movies,i don't remember seeing one,the just talk about them.

goblins are seen in the mines of moria and can be seen as different from orcs as the have very poor posture and are hunched over all the time were as orcs have a more upright posture