Plural of Focus
Both “foci” and “focuses” are accepted plurals of “focus.” Do not assume the Latin-derived “foci” makes “focuses” incorrect; dictionaries record both forms.
Both “foci” and “focuses” are accepted plurals of “focus.”
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| one center of attention or activity | focus | Use the singular form. |
| Latin-derived plural | foci | Accepted plural. |
| regular English plural | focuses | Also accepted. |
Quick tests
Meaning / construction test
Do you need the plural noun of “focus”?
If yes: Use either “foci” or “focuses,” guided by discipline and house style.
If no: Use singular “focus” when there is only one center or point of attention.
Caveat: Both “foci” and “focuses” are accepted plurals; field preference may differ, so the diagnostic is not a universal right-versus-wrong test.
Examples
The study has two main foci.
“Foci” is an accepted Latin-derived plural.
The report identifies several focuses for improvement.
“Focuses” is also an accepted plural noun.
The main focus is accessibility.
One center of attention takes the singular “focus.”
Further guidance
Core difference
Both “foci” and “focuses” are accepted plurals of “focus.”
Fast Test
Choose the plural that fits the discipline and house style, then use it consistently.
Usage Boundary
Do not assume the Latin-derived “foci” makes “focuses” incorrect; dictionaries record both forms.
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.
- Focus — Merriam-Webster (opens in a new tab)Merriam-Webster · Dictionary evidence recording both foci and focuses as plurals of focus.