据《牛津高阶英汉双解词典》：ghetto: a area of a city where many people of the same race or background live, separately from the rest of the population. Ghettos are often crowded, with bad living conditions. (相同种族或背景的人的）聚居区；贫民区 2 、the area of a town where Jews were forced to live in the past（昔日城市中的）犹太人居住区slum: a area of a city that is very poor and where the houses are dirty and in bad condition贫民窟，棚屋区就“贫民区”这个意思来讲，ghetto和slum意思很接近。

区别在于：在一个ghetto中居住的人是同一种族或背景的，而且很拥挤；ghetto是与城市中的其他区域是隔开的。

而slum没有这层意思。