orcs and goblins- what's the difference???

[AragornII]

I just wanted to point out that their is a difference between orcs and goblins in the movies. Now I know that this might just be PJ's interpretation, but in FotR, Gandlf, during his conversation with Elrond after Frodo's rescue at the ford, says:

...he's crossing orcs with goblin men, he's breeding an army...

This is in reference to Saruman. It suggests that orcs and goblins are two different creatures, because if they were the same, I don't think crossing an orc with an orc would give you an Uruk-hai. However, this is just the movies, so PJ could have added this. I checked in the book, but couldn't find it. Correct me if I'm wrong.