noun stra·tum \ˈstrā-təm, ˈstra-\

: 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

plural stra·ta \ˈstrā-tə, ˈstra-\

Full Definition of STRATUM

:  a bed or layer artificially made
a :  a sheetlike mass of sedimentary rock or earth of one kind lying between beds of other kinds
b :  a region of the sea or atmosphere that is analogous to a stratum of the earth
c :  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
a :  a part of a historical or sociological series representing a period or a stage of development
b :  a socioeconomic level of society comprising persons of the same or similar status especially with regard to education or culture
:  one of a series of layers, levels, or gradations in an ordered system <strata of thought>
:  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.

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

Attic, Byzantine, Paleolithic, cairn, core, flint, horizon, neolithic, shard
STRATUM Defined for Kids


noun stra·tum \ˈstrā-təm, ˈstra-\
plural stra·ta \-tə\

Definition of STRATUM for Kids

:  1layer 1 <a stratum of rock>
Medical Dictionary


noun stra·tum \ˈstrāt-əm, ˈstrat-\
plural stra·ta \ˈstrāt-ə, ˈstrat-\

Medical Definition of STRATUM

:  a layer of tissue <a deep stratum of the skin>
:  a statistical subpopulation


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