Ardor vs. Ardour
Cambridge labels “ardour” as UK and “ardor” as US for the same noun meaning great enthusiasm or love. This guide treats the choice as a documented spelling convention and does not invent a meaning difference between the variants.
Use “ardor” in standard US spelling and “ardour” in standard UK spelling; the spelling changes by convention, not by meaning.
Key details
Choose the right form
| Audience/style | Preferred spelling | Meaning |
|---|---|---|
| US English | ardor | same noun |
| UK English | ardour | same noun |
| mixed/international document | follow chosen house style | do not alternate without reason |
Quick tests
Regional spelling test
Is the document following a defined US or UK spelling convention?
If yes: Use the spelling required by that convention and keep it consistent.
If no: If no convention is specified, choose one accepted form for the audience and apply it consistently.
Caveat: This is a regional spelling difference, not a difference in meaning or grammatical correctness.
Examples
Her ardor for the project was obvious.
“Ardor” is the standard US spelling.
His ardour for the subject was obvious.
“Ardour” is the standard UK spelling.
The report alternates between ardor and ardour without a style reason.
Better: Choose either “ardor” or “ardour” according to the document’s regional style.
Both spellings are valid, but unexplained mixing weakens editorial consistency.
Further guidance
Core difference
Use “ardor” in standard US spelling and “ardour” in standard UK spelling; the spelling changes by convention, not by meaning.
Style Boundary
Choose the spelling that matches the audience, region, or house style, and keep that choice consistent where both forms are accepted.
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.
- Ardour — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · UK ardour and US ardor spelling distinction