stra·​tum | \ ˈstrā-təm, ˈstra- \
plural strata\ ˈstrā-​tə , ˈstra-​ \

Definition of stratum

1 : a bed or layer artificially made
2a : 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 (such 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 development
b : 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

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Synonyms for stratum


caste, class, estate, folk, gentry, order

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Is strata singular or plural?: Usage Guide

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 sense 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.

Did You Know?

In geology, a stratum is a layer of rock or soil that is distinct from those above and below it. Rock and soil strata (notice the plural form) can be seen in road cuts, cliffs, quarries, riverbanks, and sand dunes, and in pieces of limestone, slate, and shale. Archaeologists digging in historical sites are careful to note the stratum where each artifact is found. Earth scientists divide the earth's atmosphere into strata, just as oceanographers divide the ocean's depths into strata. And for social scientists, a stratum is a group of people who are similar in some way, such as education, culture, or income.

Examples of stratum in a Sentence

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

Recent Examples on the Web

Alex Makes the Strata I'm hooked on Gale Gand's strata. Alexandria Abramian-mott, House Beautiful, "Gale Gand's Recipe for Strata," 3 Jan. 2012 In the book, Alissa Quart illustrates how life in a once-secure stratum has come to resemble the endlessly anxious existence of those in the rungs below. Ginia Bellafante, New York Times, "Lesson of the Blue Wave Primaries? We’re All Struggling Now," 28 June 2018 That’s the challenge that Ms. Thurber, the director Jackson Gay and their five-member cast are trying to overcome here, using the theater’s license for empathic eloquence to bridge the gaps among social strata. Ben Brantley, New York Times, "Review: ‘Transfers’ and the Anguished Art of the College Interview," 23 Apr. 2018 The rub lay between those who studied the fossils and those who examined the rock strata, each drawing wildly different conclusions about the age of their subjects. Johnforristerross, Longreads, "Taming the Great American Desert," 2 July 2018 The assistants strain to gain entry into professional strata by working until their eyes are bleary., "Set It Up Is Not Only The Rom-Com Millennials Want, It’s The One They Need," 20 June 2018 There’s different strata of New York, and Neff represents a real important one, which is young person with artistic/professional ambitions who doesn’t have money, but is around money and people who have a lot more money than her. Recode Staff, Recode, "Full transcript: Jessica Pressler talks ‘lady grifters’ + Ken Auletta on the ‘frenemies’ of the ad business on Recode Media," 24 June 2018 Webb has a customized boat, the research vessel D Hill, that features a drilling platform for taking core samples from ancient strata below the Great Barrier Reef. Elizabeth Svoboda, Scientific American, "Cores from Coral Reefs Hold Secrets of the Seas’ Past and Future," 6 June 2018 But no one thing so seems to galvanize the masses, and the less numerous strata above, as pizza. Beth Segal,, "Il Rione Pizzeria: A passion for pizza in Gordon Square," 11 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'stratum.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of stratum

1599, in the meaning defined at sense 1

History and Etymology for stratum

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

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Statistics for stratum

Last Updated

19 Nov 2018

Look-up Popularity

Time Traveler for stratum

The first known use of stratum was in 1599

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More Definitions for stratum



English Language Learners 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


stra·​tum | \ ˈstrā-təm, ˈstra-\
plural strata\ -​tə \

Kids Definition of stratum

: layer entry 1 sense 1 a stratum of rock


stra·​tum | \ ˈstrāt-əm, ˈstrat- \
plural strata\ ˈstrāt-​ə , ˈstrat-​ \

Medical Definition of stratum

1 : a layer of tissue a deep stratum of the skin
2 : a statistical subpopulation

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Comments on stratum

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someone who never drinks alcohol

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