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noun stra·tum \ˈstrā-təm, ˈstra-\

Simple Definition of stratum

  • : one of usually many layers of a substance (such as rock)

  • : a level of society made up of people of the same rank or position

Source: Merriam-Webster's Learner's Dictionary

Full Definition of stratum

plural strata play \ˈstrā-tə, ˈstra-\

  1. 1 :  a bed or layer artificially made

  2. 2a :  a sheetlike mass of sedimentary rock or earth of one kind lying between beds of other kindsb :  a region of the sea or atmosphere that is analogous to a stratum of the earthc :  a layer of tissue <deep stratum of the skin>d :  a layer in which archaeological material (as artifacts, skeletons, and dwelling remains) is found on excavation

  3. 3a :  a part of a historical or sociological series representing a period or a stage of developmentb :  a socioeconomic level of society comprising persons of the same or similar status especially with regard to education or culture

  4. 4 :  one of a series of layers, levels, or gradations in an ordered system <strata of thought>

  5. 5 :  a statistical subpopulation

Usage Discussion of stratum

The plural strata has occasionally been used as a singular since the 18th century and is sometimes given the plural stratas <there was a strata of Paris which mere criticism of books fails to get hold of — Ezra Pound> <a Roman burial ground suggests stratas of corruption and decay — Connie Fletcher, Booklist>. Current evidence shows senses 2, 3b, and 4 so used, with 3b the most common. Singular strata is persistent but not frequent. Strata may someday establish itself as a singular like agenda, but that use is still not established.

Examples of stratum in a sentence

  1. <the lower strata of society have been hit especially hard by this economic downturn>

  2. <the level of writing in that pop novel is several strata beneath that of serious fiction>

Origin of stratum

New Latin, from Latin, spread, bed, from neuter of stratus, past participle of sternere to spread out — more at strew

First Known Use: 1599

Other Archaeology Terms

STRATUM Defined for Kids


noun stra·tum \ˈstrā-təm, ˈstra-\

Definition of stratum for Students

plural strata \-tə\

  1. :  1layer 1 <a stratum of rock>

Medical Dictionary


play play
noun stra·tum \ˈstrāt-əm, ˈstrat-\

Medical Definition of stratum

plural strata \ˈstrāt-ə, ˈstrat-\play play

  1. 1:  a layer of tissue <a deep stratum of the skin>

  2. 2:  a statistical subpopulation

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