How is limited narrator different from omniscient narrator?

An example of third person limited is the Harry Potter series, which, with the exception of a VERY few chapters is written exclusively from Harry's point of view. Third person Limited means the narration is from one character's point of view, including their thoughts and motives.

Third person Omniscient gives more options and openings for creativity since the author can be with any of the characters, including their thoughts, motivations and feelings. LOTR is a good example of third person omniscient.