Plural of Stratum
For a layer, level, social group, statistical subpopulation, or other ordinary sense of “stratum,” the plural is “strata.” Merriam-Webster notes occasional singular “strata” usage, but that does not make “stratas” the ordinary plural of “stratum.” A separate culinary noun “strata” has its own number pattern and should not be confused with this one.
The standard plural of “stratum” is “strata.”
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| one layer / level | stratum | Singular. |
| several layers / levels | strata | Standard plural. |
| culinary “strata” | separate noun | Different lexical entry and number pattern. |
Quick tests
Plural-choice test
Are you referring to more than one ordinary stratum?
If yes: Use “strata.”
If no: Use singular “stratum.”
Caveat: Occasional singular “strata” is a documented usage nuance, not a reason to replace the standard stratum → strata pattern.
Examples
The excavation revealed several distinct strata.
Multiple layers take “strata.”
This stratum contains most of the fossils.
One layer takes “stratum.”
Researchers compared income strata across regions.
Social levels take the same standard plural.
Further guidance
Core difference
Use “strata” for more than one stratum.
Fast Test
If you mean multiple layers/levels in the ordinary noun sense, choose “strata.”
Usage Boundary
Do not present “stratas” as the ordinary plural of “stratum.”
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- STRATUM | English meaning - Cambridge Dictionary (opens in a new tab)Cambridge University Press · Cambridge records strata as the plural of stratum for layers, levels, and social/geological senses.
- STRATUM Definition & Meaning - Merriam-Webster (opens in a new tab)Merriam-Webster · Merriam-Webster records plural strata and notes nonstandard/historical singular strata usage rather than making stratas the ordinary plural of stratum.