next door

adverb

1. Also next door. to, at, or in the next house on the street, especially if it is very close by, or the adjacent apartment, office, room, or the like: Go next-door and get your sister. Your sister is next-door. Her brother lives next-door.

adjective

2. being situated or living next-door: next-door neighbors.

adjective, adverb (next-door when prenominal)

1. at, in, or to the adjacent house, flat, building, etcwe live next door to the dentist; the next-door house

adv.also nextdoor, 1570s, from noun phrase next door “nearest house” (late 15c.), from next + door. Noun meaning “the people living next door” is from 1855.