nearest neighbors; immediate neighborhood
A set phrase referring to the closest neighbors in a traditional residential context. Literally 'the three houses across the street and the two houses on either side', but used more broadly for one's immediate neighbors. Often appears in discussions of community ties or mutual aid.
Relationships with one's nearest neighbors are important.
In the old days, people used to help each other among the immediate neighbors.
近所 is a general term for 'neighborhood' or 'vicinity', while 向こう三軒両隣 specifically refers to the very closest neighbors, often with a nuance of mutual obligation.
A compound of 向こう (across), 三軒 (three houses), 両 (both), and 隣 (next door), literally describing the three houses opposite and the two houses on either side. The phrase has been used since at least the Edo period to denote one's immediate neighbors.