stratum

American  

[strey-tuhm, strat-uhm] / ˈstreɪ təm, ˈstræt əm /

noun

plural

strata, 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.

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stratum British  

/ ˈstrɑːtəm /

noun

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

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stratum Scientific  

/ strā′təm,străt′əm /

plural

strata

1. 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.

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

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Usage

Strata, historically the plural of stratum, is occasionally used as a singular: The lowest economic strata consists of the permanently unemployable. Less frequently, a plural stratas occurs: Several stratas of settlement can be seen in the excavation. At present, these uses are not well established, and they are condemned in usage guides. Strata may eventually become part of a group of borrowed plurals that are now used as singulars in English, such as agenda and candelabra, but it is not yet in that category. See also agenda, criterion, media, phenomena.

Other Word Forms

• stratal adjective
• stratous adjective

Etymology

Origin of stratum

1590–1600; < Latin strātum literally, a cover, noun use of neuter of strātus, past participle of sternere to spread, strew, equivalent to strā- variant stem + -tus past participle suffix

Example Sentences

At one end, PSG is the club of the masses, drawing its fan base from every strata of the city and its suburbs.

From The Wall Street Journal

From May to October, continuing a tradition launched in 2011, visitors can pay extra to dig for their own fossils in more recent, less scientifically significant geographical strata.

From The Wall Street Journal

Layer it all in a shallow casserole dish or, if you’re feeling theatrical, a glass trifle dish, so the strata show through like geological layers of flavors.

From Salon

I thought I wanted a piece of all that; not so much the affluence, but the ease with which he moved through the world with money and social strata no deterrence.

From Los Angeles Times

Ultimately, she argues that these strata show us that when stressed, the earth reacts by changing and moving toward stability.

From Los Angeles Times