Dictionary:

adjoining

  (ə-joi'nĭng)

Neighboring; contiguous.

Contiguous; attaching; sharing a common border, as in adjoining properties.

contiguous; attaching; sharing a common border.
Example: A warehouse with adjoining office space.

adjective

Sharing a common boundary: adjacent, conterminous, contiguous, next. See near/far/distance.

Definition: being next to
Antonyms: detached, divided, separate