stra·​tum | \ ˈstrā-təm How to pronounce stratum (audio) , ˈstra- How to pronounce stratum (audio) \
plural strata\ ˈstrā-​tə How to pronounce stratum (audio) , ˈstra-​ How to pronounce stratum (audio) \

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

Synonyms for stratum


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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. We should also point out that there is a derivative culinary term strata, entered separately in this dictionary, which has a singular sense, denoting a layered and baked dish whose ingredients include eggs, bread, and cheese. For the edible strata the logical and usual plural is stratas, but strata is also used as a secondary plural (as in "several ham and cheese strata"), presumably by those for whom stratas looks like an error.

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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 Extra musicians in the boxes next to the stage create antiphonal effects around the audience; electronics provide creepiness for the ghost scenes and others, while a chorus of eight singers in the pit adds an additional stratum of sound. Heidi Waleson, WSJ, 18 May 2022 Italian capitalists relied on a stratum of national opinion-makers who would gently signal the need for reforms, while otherwise keeping the political imagination of Italians in acceptable bounds. Thomas Meaney, The New Republic, 30 Mar. 2022 My lack of prowess on the very things that define New York’s social stratum meant that I was often ostracized from the insular Wall Street circle. Solo Ceesay, Rolling Stone, 23 Feb. 2022 Joe Keller had just joined the foggy stratum of the hundreds or maybe thousands of people who’ve gone missing on our federal public lands. Jon Billman, Outside Online, 13 Mar. 2017 The event caps off a particularly tumultuous year for the stratum of rap on which both Kanye and Drake reside. Jeff Ihaza, Rolling Stone, 10 Dec. 2021 The excavations shed light on a stratum of society and way of life that is still little known. Rebecca Ann Hughes, Forbes, 8 Nov. 2021 In this stratum of high-but-not-highest-end architecture, various degrees of structural complexity and an assortment of different programs are all packed into plain boxes distinguished by a few half-hearted accents. Justin Davidson, Curbed, 24 Nov. 2021 At the same time, a different stratum of Amazon's empire presented another set of unruly vulnerabilities. Will Evans, Wired, 18 Nov. 2021 See More

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.

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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Time Traveler for stratum

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The first known use of stratum was in 1599

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Dictionary Entries Near stratum



stratum corneum

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Statistics for stratum

Cite this Entry

“Stratum.” Dictionary, Merriam-Webster, Accessed 12 Aug. 2022.

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More Definitions for stratum


stra·​tum | \ ˈstrā-təm How to pronounce stratum (audio) , ˈstra- \
plural strata\ -​tə \

Kids Definition of stratum

: layer entry 1 sense 1 a stratum of rock


stra·​tum | \ ˈstrāt-əm How to pronounce stratum (audio) , ˈstrat- How to pronounce stratum (audio) \
plural strata\ ˈstrāt-​ə How to pronounce stratum (audio) , ˈstrat-​ How to pronounce stratum (audio) \

Medical Definition of stratum

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

More from Merriam-Webster on stratum

Nglish: Translation of stratum for Spanish Speakers

Britannica English: Translation of stratum for Arabic Speakers Encyclopedia article about stratum


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