What is the difference between "citizen" and "denizen"

Citizen: 1. A legally recognized subject ornational of a state or commonwealth, either native or naturalized. 2. An inhabitant of a particular town or city.

Denizen: 1. An inhabitant or occupant of a particular place.

Same thing?

I would say the answer depends on how technical we're being.

A citizen of the United States is a legal resident who has been processed by the government as being a member of the United States.

A denizen of the United States is simply someone that lives there.

Technically speaking, one could never be, for example, a citizen of the Earth -- but we're all denizens of the Earth.

I can think of three types of use where denizen works, and citizen doesn't.

• For a much smaller area, especially one not defined by government: "Truman Capote was a long-time denizen of Manhattan's social scene."
• For animals: "Rodents Of Unusual Size, like other Fire Swamp denizens, are rarely seen by humans."
• With a derogatory connotation: "Dick Armey, like other K Street denizens, likes few things more than tax cuts for billionaires."

"Citizen" means a person who is not just present in a city or other conurbation, but at least potential part of its social body.

"Denizen" is a much more general word which is not limited to humans, and not limited to civilised or organised places. It often has a connotation of wildness.