The Collaborative International Dictionary of English v.0.48:

Adjoin \Ad*join"\, v. t. [imp. & p. p. Adjoined; p. pr. & vb.
   n. Adjoining.] [OE. ajoinen, OF. ajoindre, F. adjoindre,
   fr. L. adjungere; ad + jungere to join. See Join, and cf.
   Adjunct.]
   To join or unite to; to lie contiguous to; to be in contact
   with; to attach; to append.
   [1913 Webster]

         Corrections . . . should be, as remarks, adjoined by
         way of note.                             --Watts.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Adjoining \Ad*join"ing\, a.
   Joining to; contiguous; adjacent; as, an adjoining room. "The
   adjoining fane." --Dryden.
   [1913 Webster]

         Upon the hills adjoining to the city.    --Shak.
   [1913 Webster]

   Syn: Adjacent; contiguous; near; neighboring; abutting;
        bordering. See Adjacent.
        [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "adjoining":
   abutting, adjacent, bordering, connecting, conterminous,
   contiguous, coterminous, end to end, endways, endwise,
   face to face, immediate, joined, juxtaposed, juxtapositional,
   juxtapositive, neighbor, neighboring, next, next to, touching