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
Full Definition of stratum
plural stra·ta play \ˈstrā-tə, ˈstra-\
1 : a bed or layer artificially made
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
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 : one of a series of layers, levels, or gradations in an ordered system <strata of thought>
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
<the lower strata of society have been hit especially hard by this economic downturn>
<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
STRATUM Defined for Kids
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