adj. Being in contact at some point or line; joining to; contiguous; bordering: an adjoining room.
v. Present participle of adjoin.
the GNU version of the Collaborative International Dictionary of English
adj. Joining to; contiguous; adjacent.
Word Usage
"I remember teaching two classes (in adjoining classrooms) simultaneously – timing the group work so I could whip next door and do a bit of whole-class stuff, and then out again."