Plural of Basis
“Basis” forms the irregular plural “bases.” The spelling can be confusing because “bases” is also the written plural of “base,” but the plural of “basis” has its own pronunciation. In grammar, use “basis” for one underlying foundation or method and “bases” for more than one.
The plural of “basis” is “bases.” The plural is pronounced with a long “ee” sound in the final syllable, distinguishing it from the singular “basis.”
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| one underlying foundation/method | basis | Use the singular. |
| two or more | bases | Use the irregular plural of “basis.” |
| same spelling from noun “base” | bases | Use context and pronunciation to identify the lexical source. |
Quick tests
Plural-choice test
Do you mean more than one basis?
If yes: Use “bases.”
If no: Use singular “basis”; if the word comes from “base,” analyze that separate noun instead.
Caveat: The spelling “bases” can represent more than one lexical family, so context remains essential.
Examples
The decision rested on two separate bases.
Here “bases” is the plural of “basis.”
There is no legal basis for the claim.
One takes singular “basis.”
The analysis used several independent bases for comparison.
The irregular plural is required after a plural quantity.
Further guidance
Core difference
Use “basis” for one and “bases” for more than one; rely on meaning and pronunciation to distinguish the homographic plural from “base.”
Fast Test
If you can replace the phrase with “two foundations/methods,” use plural “bases.”
Usage Boundary
Do not turn the page into a broad base-versus-basis vocabulary comparison; the relevant issue is the irregular plural and its pronunciation.
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.
- BASIS | English meaning - Cambridge Dictionary (opens in a new tab)Cambridge University Press · Cambridge gives bases as the plural of basis with its distinct pronunciation, supporting an irregular-plural guide that must distinguish bases from the plural of base.