Plural of Apex
“Apex” has two standard plural forms: the regular English “apexes” and the Latin-derived “apices.” Authoritative dictionaries recognize both, so the editorial task is choosing a form that fits the audience or field rather than declaring one universally correct.
Both “apexes” and “apices” are accepted plurals of “apex.” Use the form preferred by your field or publication, and keep it consistent.
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| regular English plural | apexes | Accepted. |
| Latin-derived plural | apices | Accepted. |
| edited technical document | match established convention | Consistency is the main practical rule when both are allowed. |
Quick tests
Plural-choice test
Does your field, source, or house style already use one plural?
If yes: Use that form consistently.
If no: Either “apexes” or “apices” is accepted.
Caveat: Any field preference should be presented as convention, not universal grammar.
Examples
The two apexes were measured separately.
The regular plural is accepted.
The diagram labels the apices of the shapes.
The Latin-derived plural is also accepted.
Both apexes lie above the reference line.
The regular plural is valid in technical prose too unless a convention says otherwise.
Further guidance
Core difference
Choose either accepted plural and follow any established field or house-style preference.
Fast Test
If the document already uses one plural or a field convention is clear, match it; otherwise either standard form works.
Usage Boundary
Do not claim that the Latin-derived form is always more correct or that the regular English plural is nonstandard.
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.
- APEX | English meaning - Cambridge Dictionary (opens in a new tab)Cambridge University Press · Cambridge gives apexes or apices as accepted plurals, supporting a genuine variant-form decision.