Sentence:  ... concentrating the Jewish community into <WSD>ghettoes</WSD>. The Germans not only started the <WSD>ghettoes</WSD>, but they had also opened a concentration camp ... 
Meaning of the word marked with <WSD> tags:  An (often walled) area of a city in which Jews are concentrated by force and law. (Used particularly of areas in medieval Italy and in Nazi-controlled Europe.)