noun
Sociological term referring to the segment of society with low income, education, or social status. Often used in discussions of social stratification and inequality.
下流社会の拡大が社会問題になっている。
The expansion of the lower classes has become a social issue.
Compound of 下流 (karyū, 'downstream; lower class') and 社会 (shakai, 'society'). The term gained popularity in sociological discourse in the early 2000s.