Good fences make good neighbors.
Prov. It is easier to be friendly with your neighbor if neither of you trespasses upon the other's property or privacy. Jane: The guy next door is letting his party guests wander across our lawn again. Alan: I guess we'll have to build a fence there. Good fences make good neighbors, like they say.
neighbor on something
to be directly adjacent to something. Our house neighbors on a park. The park neighbors on a stretch of beach.
one's next-door neighbor
the person living in the house or apartment closest to one's own. My next-door neighbor came over to borrow a shovel. I will be visiting our next-door neighbor if you need me.