stratification
n.分层; 成层 复数：stratifications 牛津词典 noun 分层；成层the pision of sth into different layers or groupssocial stratification社会阶层化 柯林斯词典 N-UNCOUNT (尤指社会的)分层，形成阶层Stratification is the pision of something, especially society, into different classes or layers...