Anatomy The part of the body joining the head to the shoulders or trunk. A narrow or constricted area of a bodily structure, as of a bone, that joins its parts; a cervix. The part of a tooth between the crown and root. The part of a garment around or near the neck. A relatively narrow elongation, projection, or connecting part: a neck of land; the neck of a flask. Music The narrow part along which the strings of an instrument extend to the pegs. Printing See beard. Geology Solidified lava filling the vent of an extinct volcano. The siphon of a bivalve mollusk, such as a clam. A narrow margin: won by a neck.