Neighbor and neighbour mean exactly the same thing; only the spelling changes with the country. Neighbor is standard in American English, neighbour in British English. A useful memory hook: both come from the same Old English root meaning near-dweller, so the extra u in neighbour is simply the British convention, as in colour or favour.
The core difference
Neighbor and neighbour are the same word for someone or something that lives or sits close by, spelled differently in American and British English.
- neighbor — the American spelling, for a person or country close by: Our new neighbor introduced herself with a plate of cookies.
- neighbour — the British spelling, used the same way: Our neighbour kindly watered the plants while we were away.
How to tell them apart
Both spellings trace back to the Old English nēahgebūr, literally near-dweller, so there is no difference in meaning between neighbor and neighbour. The choice is simply about audience: American publications, software, and readers expect neighbor, while British, Australian, and most Commonwealth readers expect neighbour.
The word also works as a verb for things that sit close together, such as a bakery that neighbors a park, or a village that neighbours a forest reserve. The verb follows the same spelling rule as the noun.
