I. ˌnext ˈdoor 1 BrE AmE adverb
1 . in the house, room etc next to yours or someone else’s:
the boy next door
Her office is just next door.
2 . next door to something next to another building, room etc:
They live next door to the shop.
II. next door 2 BrE AmE noun [uncountable] British English informal
the people living in the house or apartment next to yours SYN neighbour :
Have you seen next door’s new car?