Word
stratum
Phoneticsstra·tum, stress on the first syllable
US/ˈstɹætəm/
UK/stɹˈɑːtəm/
Countable noun
Definition
n. a layer of rock, soil, or other material, often under the ground. People also use it for a level or group in society, like a social class.
n. a distinct, superimposed layer of sedimentary rock, soil, or other material, or a level within a social or conceptual hierarchy.
Examples
“This dark stratum holds water under the field.”
“The archaeologists dig through each stratum to date the tools they find in the soil.”
“The cliff face reveals alternating strata of sandstone and shale, each stratum recording millions of years of shifting seas and river deltas.”
Examples
simple
“This dark stratum holds water under the field.”
contextual
“The archaeologists dig through each stratum to date the tools they find in the soil.”
complex
“The cliff face reveals alternating strata of sandstone and shale, each stratum recording millions of years of shifting seas and river deltas.”
Collocations
Common phrases and expressions where native English speakers use the word “stratum” in context.
Verb
01. belong to stratum
“They proudly belonged to the educated stratum of society.”
verb + prep + noun
02. drill into stratum
“Engineers drilled into the stratum to test its stability.”
verb + prep + noun
03. examine stratum
“Geologists examined each stratum for traces of oil.”
verb + noun
04. expose stratum
“The landslide exposed a stratum rich in marine fossils.”
verb + noun
05. occur in stratum
“Trilobite fossils commonly occur in this stratum.”
verb + prep + noun
06. penetrate stratum
“The drill failed to penetrate the hard stratum below.”
verb + noun
07. reveal stratum
“The road cut revealed a stratum of volcanic ash.”
verb + noun
Adjective
08. overlying stratum
“Heavy erosion removed the overlying stratum of topsoil.”
adj + noun
09. sedimentary stratum
“Each sedimentary stratum records a distinct period of deposition.”
adj + noun
10. date the sedimentary stratum
“Scientists used carbon dating to date the sedimentary stratum.”
11. expose an underlying stratum
“The quarry face exposes an underlying stratum of sandstone.”
12. penetrate the overlying stratum
“Roots cannot penetrate the overlying stratum of compacted clay.”
Usage
Plural is strata; stratum takes a singular verb, strata takes a plural verb.
Pitfall
the stratas of rock
the strata of rock
The plural of stratum is strata, not stratas.
Real-World Examples
“When the stratum corneum becomes excessively dry, the skin may suffer from itchiness, flakiness, inflammation, a leathery texture, and an overall unattractive appearance.” Etymology
Borrowed from Latin strātum (“a spread for a bed, coverlet, quilt, blanket; a pillow, bolster; a bed”), neuter singular of strātus, perfect passive participle of sternō (“spread”). Doublet of estrade.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Word family
NOUN
Domains
- Exam level
- CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.C1 AdvancedIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.7.0–8.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 5.0–5.595–113TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.945–990
- Frequency
- Occasional
- Level
- C1 · Advanced
- Updated
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