|—n , pl -ta, -tums|
|1.||(usually plural) any of the distinct layers into which sedimentary rocks are divided|
|2.||biology a single layer of tissue or cells|
|3.||a layer of any material, esp one of several parallel layers|
|4.||a layer of ocean or atmosphere either naturally or arbitrarily demarcated|
|5.||a level of a social hierarchy that is distinguished according to such criteria as educational achievement or caste status|
|[C16: via New Latin from Latin: something strewn, from sternere to scatter]|
stratum stra·tum (strā'təm, strāt'əm)
n. pl. stra·tums or stra·ta (-tə)
A horizontal layer of material, especially one of several parallel layers arranged one on top of another.
Any of the layers of differentiated tissue forming an anatomical structure.