[] one of several levels in an organization or a system阶层；等级◆More women are reaching the top tier of management.更多的女性做到了最高管理层。◆a two-tier pay structure二元工资结构one of several levels of quality（质量）级别◆a place in the top tier of biotech companies生物技术公司的顶级职位first tier second tier top-tier two-tier