Pants/Legends

Pants are clothes that one wears on it's legs. Some Sentient speices such as Ewoks and Wookiees don't where pants. Han Solo and most humans wear pants.

Behind the Scenes
In ANH the producers where worried because Chewbacca doesn't wear pants at all. This inconsistency caused all wookiees in EU and revenge of the sith to not be wearing pants.