Correct spelling, explanation: the form you should use, neighbor or neighbour, depends on the variety of English you are using or the conventions of the region in which you are writing. Neighbor (without the -u) is the standard spelling in American English. If you are writing in American English or for an American audience, use the word neighbor. Neighbour (with the -u) is the standard spelling in British English and in many other varieties of English, including Canadian, Australian, and New Zealand English. If you are writing in any of these varieties of English, or if you are following British English conventions, use neighbour.

Definition of neighbor:
noun, someone who lives near you
My neighbor kindly offered to help me with my gardening when I was away.
The neighborhood picnic is a great opportunity for neighbors to get to know each other better.

Collocations with neighbor:
Some most commonly used collocations include:
1. Next-door neighbor: refers to the person or family living in the house or apartment adjacent to yours.
Our next-door neighbors are really friendly.
2. Friendly neighbor: describes a neighbor who is pleasant, sociable, and easy to get along with.
We’re lucky to have such friendly neighbors.
3. Nosy neighbor: refers to a neighbor who is overly curious and often peeks into other people’s affairs or tries to learn about their private matters.
Our nosy neighbor always seems to know everyone’s business.
4. Good neighbor policy: a set of principles or practices aimed at maintaining peaceful and friendly relations with neighboring countries or communities.
The government’s good neighbor policy has improved diplomatic relations with our neighboring countries.

Correct spelling, explanation: both neighbor and neighbour are considered correct within their respective English varieties. The difference in spelling primarily stems from historical language development and regional preferences. In terms of meaning and usage, neighbor and neighbour are essentially the same. They both refer to a person who lives near you or in close proximity to your residence. Neighbor is standard in American English, whereas neighbour is standard in British English, but they can be used interchangeably.