stratum

noun

stra·​tum ˈstrā-təm  ˈstra- 

plural strata ˈstrā-tə  ˈstra- 

1

: a bed or layer artificially made

2

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 (such as artifacts, skeletons, and dwelling remains) is found on excavation

3

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

4

: one of a series of layers, levels, or gradations in an ordered system

strata of thought

5

: a statistical subpopulation

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.

Synonyms

• caste
• class
• estate
• folk
• gentry
• order

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

In those remains, the team found high rates of tobacco spanning every stratum of Victorian society. —Byandrew Curry, science.org, 4 Oct. 2024

The museum’s former chancellor, George Osborne, reportedly approached Nandy, setting the stage for talks across an institutional stratum in which many don’t see eye to eye on the issue. —Daniel Cassady, ARTnews.com, 24 Sep. 2024

And then, again, below this middle stratum, more bare canvas flecked by a few further coloristic footnotes. —Barry Schwabsky, ARTnews.com, 17 July 2024

The researchers noted, however, that some animal protein was consumed, as cut marks were observed on the faunal assemblage, a group of animal fossils found together in a stratum, providing evidence of the butchery and processing of animals at that time. —Erin Clack, Peoplemag, 19 May 2024

Word History

Etymology

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

First Known Use

1599, in the meaning defined at sense 1

Phrases Containing stratum

• stratum corneum

Kids Definition

stratum

noun

stra·​tum ˈstrāt-əm  ˈstrat- 

plural strata -ə 

1

: a layer of a substance

especially : one of a series of layers

a rock stratum

a stratum of earth

the deep stratum of the skin

2

: a level of society consisting of persons of the same or similar rank or position

Medical Definition

stratum

noun

stra·​tum ˈstrāt-əm  ˈstrat- 

plural strata ˈstrāt-ə  ˈstrat- 

1

: a layer of tissue

a deep stratum of the skin

2

: a statistical subpopulation