noun, plural strata
[strey-tuh, strat-uh] /ˈstreɪ tə, ˈstræt ə/ (Show IPA), stratums.
a layer of material, naturally or artificially formed, often one of a number of parallel layers one upon another:
a stratum of ancient foundations.
one of a number of portions or divisions likened to layers or levels:
an allegory with many strata of meaning.
Geology. a single bed of sedimentary rock, generally consisting of one kind of matter representing continuous deposition.
Biology. a layer of tissue; lamella.
Ecology. (in a plant community) a layer of vegetation, usually of the same or similar height.
a layer of the ocean or the atmosphere distinguished by natural or arbitrary limits.
Sociology. a level or grade of a people or population with reference to social position, education, etc.:
the lowest stratum of society.
Linguistics. (in stratificational grammar) a major subdivision of linguistic structure.
Compare level (def 17).
noun (pl) -ta (-tə), -tums
(usually pl) any of the distinct layers into which sedimentary rocks are divided
(biology) a single layer of tissue or cells
a layer of any material, esp one of several parallel layers
a layer of ocean or atmosphere either naturally or arbitrarily demarcated
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.
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.
- Stratum compactum
stratum compactum stratum com·pac·tum (kəm-pāk’təm) n. The superficial layer of decidual tissue in the pregnant uterus.
- Stratum corneum
stratum corneum stratum cor·ne·um (kôr’nē-əm) n. The horny outer layer of the epidermis, consisting of several layers of flat, keratinized, nonnucleated, dead or peeling cells. Also called corneal layer, horny layer.
- Stratum functionale
stratum functionale stratum func·tion·a·le (fŭngk’shə-nā’lē) n. The endometrium except for the basal layer.
- Stratum lucidum
stratum lucidum stratum lu·ci·dum (lōō’sĭ-dəm) n. See clear layer of epidermis.