聚居区 typically labels a geographic area where a particular ethnic, religious, or national group is concentrated - minority enclaves, immigrant neighborhoods. Compare to 居住区 (generic residential area) which has no group connotation.
memory
聚 (gather) + 居 (reside) + 区 (area) = 'gather-reside area.' Each character contributes a piece: who, what they do there, what kind of place.
