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

Keep scrolling for more

Synonyms for stratum


Visit the Thesaurus for More 

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.

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 The totality of the carnage inflicted by Wilson — no one has amassed more penalty minutes over the last eight seasons, according to Hockey Reference — has elicited criticism from every stratum of the sport, plus all corners of social media. New York Times, 4 May 2021 When buried in fresh snow during the storm, this layer forms a hazardous stratum that provides poor support to the snow above and often releases, resulting in avalanches. Douglas Preston, The New Yorker, 10 May 2021 The touched girls are a big hit, but this stratum of London is dead set on segregation. Amanda Whiting, Vulture, 18 Apr. 2021 The erotic massage economy has become ubiquitous in American culture and touches every socio-economic stratum. Will Yakowicz, Forbes, 4 Apr. 2021 The sidewalks were silicone-slick; a bare patch of sidewalk hid a slight stratum of ice that would upend you in a second if the dog bolted on the leash. Star Tribune, 19 Mar. 2021 The names piled up like geological deposits, each stratum incorporating the titans and trends of its time. John Gurda, Milwaukee Journal Sentinel, 4 Mar. 2021 Launching a firm to cater to a tiny, ultrawealthy stratum may sound counterintuitive at a time when spindly new condo towers stand empty and swaying and the city’s status as the global center of culture and wealth is uncertain. Andrew Rice, Curbed, 18 Feb. 2021 Prior to the Gilded Age, classical music in this country enjoyed a comparatively democratic existence, performed alongside jugglers and vaudeville tunes in raucous theaters filled with every stratum of society. Robert Jackson Wood, The New Republic, 10 Dec. 2020

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.

See More

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

Keep scrolling for more

Learn More About stratum

Time Traveler for stratum

Time Traveler

The first known use of stratum was in 1599

See more words from the same year

Statistics for stratum

Last Updated

25 May 2021

Cite this Entry

“Stratum.” Dictionary, Merriam-Webster, Accessed 24 Jun. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

Keep scrolling for more

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 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


Test Your Vocabulary

Return of Name that Color!

  • a light greenish blue color
  • Name that color:
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!