strata

UK: /ˈstrɑːtə/

US: /ˈstreɪtə, ˈstrætə, ˈstrɑtə/

US: (strā′tə, strat′ə, strä′tə)

From stratum (n):

strata

npl

stratums

npl

WordReference Random House Learner's Dictionary of American English © 2025

stra•ta /ˈstreɪtə, ˈstrætə, ˈstrɑtə/   n. [plural]

1. a pl. of stratum.

See -strat-.

WordReference Random House Unabridged Dictionary of American English © 2025

stra•ta  (strā′tə, strat′ə, strä′tə), n. 

1. a pl. of stratum. 
2. (usually considered nonstandard) stratum.

Usage

See stratum. 

Collins Concise English Dictionary © HarperCollins Publishers::

strata / ˈstrɑːtə/ noun

1. a plural of stratum

USAGE
Strata is sometimes wrongly used as a singular noun: this stratum (not strata) of society is often disregarded

WordReference Random House Learner's Dictionary of American English © 2025

stra•tum /ˈstreɪtəm, ˈstrætəm/   n. [countable] , pl. stra•ta /ˈstreɪtə, ˈstrætə/  stra•tums. 

1. a layer of something, often formed one upon another:
   a stratum of skin tissue.
2. a layer;
   level:
   That story has many strata of meanings.
3. Geology a single bed or layer of rock, consisting of one kind of material.
4. Sociology a level or grade of a people in a society, esp. with reference to social position and education:
   How could he hope to rise from the lowest stratum of society?

See -strat-.

WordReference Random House Unabridged Dictionary of American English © 2025

stra•tum  (strā′təm, strat′əm), n., pl. stra•ta (strā′tə, strat′ə), stra•tums. 

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. Oceanography 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. Cf. level (def. 18).

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

stra′tous, adj. 
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, phenomenon. 

Collins Concise English Dictionary © HarperCollins Publishers::

stratum / ˈstrɑːtəm/ noun ( -ta / -tə/, -tums)

1. (usually plural) any of the distinct layers into which sedimentary rocks are divided
2. 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

Etymology: 16th Century: via New Latin from Latin: something strewn, from sternere to scatter

ˈstratal adjective