These words refer to things near by or to things that touch each other. Neighbouring is the most informal of these and suggests only that things are close to each other but not necessarily touching: a shopping centre that drew its customers from the neighbouring communities; no one in the neighbouring flats was awakened by the sounds. Adjoining indicates a closer relationship than neighbouring , suggesting a side-by-side placement having a common boundary: asking the hotel for adjoining rooms with a door between them; French doors that revealed the adjoining patio. Abutting indicates an even closer relationship than adjoining, stressing an actual touching of elements, although not necessarily a side-by-side placement. The special implication here is of things placed together by design to gain strength or structural soundness: the wall and its abutting chimney-piece; a pattern of abutting breakwaters. When these implications are not present, the word functions much as adjoining , except that it does not necessarily suggest a side-by-side relation: a number of chapels abutting the apse of the cathedral. In describing two houses or buildings, semi-detached involves even closer contact than abutting or adjoining because there is usually a wall common to both buildings: They lived in a semi-detached cottage in Paddington. Contiguous is more formal than adjoining and abutting and is much less specific about the actual placement of elements that it refers to. Thus any kind of contact whatsoever can be indicated: back-door gardens that were contiguous to each other; a hallway that was contiguous to all the rooms of the flat.

Adjacent can suggest a relationship like that indicated by neighbouring : an explosion that brought people pouring out of the adjacent houses. It can also indicate the sharing of a common boundary in a side-by-side arrangement, as in the geometry term: adjacent angles; adjacent blocks of land. But the word has a special use to indicate things of the same kind that do not touch but are not separated from each other by things like them: adjacent farmhouses. Juxtaposed also has use distinct from those of other words here. While it can function like neighbouring or adjoining , it specifically suggests incongruous elements brought into close contact; the word often carries connotations of conflict, abruptness of placement, or surprise at contrasts: a city in which ancient and modern features are strikingly juxtaposed ; opposing forces that found themselves juxtaposed the next morning on either side of the broad river.