Stratum

noun, plural strata
[strey-tuh, strat-uh] /ˈstreɪ tə, ˈstræt ə/ (Show IPA), stratums.
1.
a layer of material, naturally or artificially formed, often one of a number of parallel layers one upon another:
a stratum of ancient foundations.
2.
one of a number of portions or divisions likened to layers or levels:
an allegory with many strata of meaning.
3.
Geology. a single bed of sedimentary rock, generally consisting of one kind of matter representing continuous deposition.
4.
Biology. a layer of tissue; lamella.
5.
Ecology. (in a plant community) a layer of vegetation, usually of the same or similar height.
6.
a layer of the ocean or the atmosphere distinguished by natural or arbitrary limits.
7.
Sociology. a level or grade of a people or population with reference to social position, education, etc.:
the lowest stratum of society.
8.
Linguistics. (in stratificational grammar) a major subdivision of linguistic structure.
Compare level (def 17).
noun (pl) -ta (-tə), -tums
1.
(usually pl) 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

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.

stra’tal (-təl) adj.
stratum
(strā’təm, strāt’əm)
Plural strata or stratums

A layer of sedimentary rock whose composition is more or less the same throughout and that is visibly different from the rock layers above and below it.

A layer of tissue, as of the skin or another organ.