stratum
n. （组织的）层；[地质] 地层；社会阶层
复数 strata或stratums
例句
It was an enormous task that affected every stratum of society.
这是一项影响到社会各阶层的重大任务。
《柯林斯英汉双解大词典》
Tramps are from the lowest stratum of society.
流浪汉来自社会最下层。
Mossy fibres terminate in the stratum lucidum of area CA3.
苔藓纤维终止于 CA3 区透明层。
