adjacent(lying next to, close, or contiguous; neighboring) adjective [UK: ə.ˈdʒeɪsnt] [US: ə.ˈdʒeɪ.sənt]France is adjacent to Spain. = Francia es colindante a España.
adjoining(being in contact at some point) adjective [UK: ə.ˈdʒɔɪn.ɪŋ] [US: ə.ˌdʒɔɪn.ɪŋ]
bordering(having a common boundary or border) adjective [UK: ˈbɔː.dər.ɪŋ] [US: ˈbɔːr.dər.ɪŋ]
contiguous(connecting without a break) adjective [UK: kən.ˈtɪ.ɡjʊəs] [US: kən.ˈtɪ.ɡjuːəs]