noun In medieval music, a rhythmic linear technique using the alternation of notes, pitches, or chords. A single melody is shared between two (or occasionally more) voices such that alternately one voice sounds while the other rests.
noun (Can we verify this sense?) A narrow passageway or opening between buildings, typically designed to facilitate access or movement between separate architectural structures.
noun Any small gap or opening; often used to describe a narrow space that allows for movement or connection between two areas.