What does denizen mean?

You are correct!

From our dictionary:

den•i•zen

Pronunciation: (den'u-zun), [key]
n.
1. an inhabitant; resident.
2. a person who regularly frequents a place; habitué: the denizens of a local bar.
3. Brit.an alien admitted to residence and to certain rights of citizenship in a country.
4. anything adapted to a new place, condition, etc., as an animal or plant not indigenous to a place but successfully naturalized.

v.t.
to make a denizen of.