“Vigor” is the US spelling and “vigour” is the UK spelling for the same noun meaning strength, energy, or force. Match the regional variety or house style used elsewhere in the text. The forms differ by regional spelling rather than meaning.
ReviewedEvidence2 sourcesSectionEnglish Usage
Quick answer
“Vigor” is the US spelling and “vigour” is the UK spelling for the same noun meaning strength, energy, or force. Match the regional variety or house style used elsewhere in the text.
Key details
Confusion Familyregional-spelling
Noun Variant ScopeThe forms differ by regional spelling rather than meaning.
Rule Familyregional-orthography
Termsvigor, vigour
Further guidance
Core difference
“Vigor” is the US spelling and “vigour” is the UK spelling for the same noun meaning strength, energy, or force. Match the regional variety or house style used elsewhere in the text.
Fast Test
Choose by meaning, grammatical function, and documented regional convention rather than treating every visible variant as an error.
Variant Boundary
The forms differ by regional spelling rather than meaning.
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.
“Aging” and “ageing” are established regional spellings. Cambridge labels aging as US and ageing as UK, so the choice should follow the intended variety or house style.
“Analyze” is the standard US spelling and “analyse” is the standard UK spelling of the same verb. The distinction is regional spelling; use the form that matches the target variety or editorial style.
“Behavior” is the US spelling and “behaviour” is the UK spelling. Use the form consistent with the regional variety or editorial style of the document.
Both “canceled” and “cancelled” are standard past-tense spellings of “cancel”; US English usually uses one l, while UK English normally uses two. Cambridge records the -ll- forms and notes that US English usually uses -l-, so the difference should be presented as a regional preference rather than a correctness split.
