tier
n
any of a series of rows (esp of seats) or parts of a structure placed one above the other 一排(尤指座位); (阶梯式的)一层
a box in the first tier, ie in atheatre (剧院中的)第一排的一个包厢
a wedding-cakewith three tiers/a three-tier wedding-cake 有三层的结婚蛋糕. =>illus at layer 见 layer 插图.