What does Naturalized citizen mean?
A naturalized citizen is someone not born in the country but has obtained citizenship later. This usually happen through marriage or adoption and I believe can also happen if you are a dependent of a citizen. So if you had the US citizenship and your mom or dad lived in Europe or so, they could get the citizenship through you if they were to come to the states. This usually takes some time and I believe they have to have a job. The only difference between a green card holder and a naturalized citizen is that you can vote.