I hope it is a comfort to you to know that as an older person who grew up in the Baltimore-Washington area and has stayed well-informed all my life, I have never heard that term used except as a way to indicate the location of a particular camp; although I am aware that Poles were targeted as well as Jews, gypsies and homosexuals. My perception was that most of the camps were in Germany.
Probably a little more than half of all concentration camps were in occupied countries. All of the death camps were in Poland. There are maps available of the locations and types.