tier
noun [ C ] uk/tɪər/ us/tɪr/
（多层、多层次中的）一层
one of several layers or levels
We sat in one of the upper tiers of the football stands. 我们坐在足球场看台的上层位置。
My wedding cake had four tiers, each supported by small pillars. 我的结婚蛋糕有4层，每层都由小柱子撑着。
I don't understand why you think we need yet another tier of management. 我不明白你为什么认为我们还需要一个管理层级。
tier
verb [ T often passive ] uk/tɪər/ us/tɪr/
层叠;层层排列
to arrange or organize something in tiers
The seats in the theatre were steeply tiered. 剧院的座位呈陡直的阶梯状排列。