tier
/tɪə(r)/noun
1- a row or level of a structure, typically one of a series of rows placed one above the other and successively receding or diminishing in size（阶梯式的）一排; 一层：
a tier of seats
一排座位
in combination the room was full of three-tier metal bunks.房间里摆满了三层金属床。
1.1
- one of a number of successively overlapping ruffles or flounces on a garment（衣服的）一层褶裥（或荷叶边）。
1.2
- a level or grade within the hierarchy of an organization or system阶层; 等级：
companies have taken out a tier of management to save money.
公司已经撤销了一个管理层以省钱。
派生词
tiered
adjective词源
late 15th cent.: from French tire 'sequence， order'， from tirer 'elongate， draw'.