Plural of Hypothesis
“Hypothesis” changes to “hypotheses” in the plural. The spelling changes from -sis to -ses, and the plural has a corresponding pronunciation change. This page covers the noun form only, not how to design or write a research hypothesis.
The plural of “hypothesis” is “hypotheses.”
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| one proposed explanation | hypothesis | Singular. |
| two or more | hypotheses | Standard plural. |
| writing/research method | separate task | This page covers noun form only. |
Quick tests
Plural-choice test
Are you referring to more than one hypothesis?
If yes: Use “hypotheses.”
If no: Use singular “hypothesis.”
Caveat: The plural pronunciation changes along with the spelling; consult the cited dictionary pronunciation if that distinction matters.
Examples
The paper compares three hypotheses.
More than one takes “hypotheses.”
Her hypothesis was testable.
One takes singular “hypothesis.”
Several hypotheses remain plausible.
The plural noun takes plural agreement.
Further guidance
Core difference
Use “hypothesis” for one and “hypotheses” for more than one.
Fast Test
If a plural quantity or plural agreement is present, choose “hypotheses.”
Usage Boundary
Do not form the standard plural as “hypothesises” or “hypothesises.”
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.
- HYPOTHESIS | English meaning - Cambridge Dictionary (opens in a new tab)Cambridge University Press · Cambridge gives hypotheses as the plural of hypothesis and records the plural pronunciation.