Gordon recognized that in addition to intermarriage within religions, social class and race also intersected, forming what he called "ethclass."

It is "True".

Ethclass is a social class characterized by their intersection of religious and ethnic limits; the term was presented by Milton Myron Gordon who is an American sociologist. He is most noted for having conceived a hypothesis on the Seven Phases of Assimilation which in American life is the role of race, religion, and national sources.