commissure

n. [ L. commissura a joining together: cf. F. commissure. See Commit. ] 1. A joint, seam, or closure; the place where two bodies, or parts of a body, meet and unite; an interstice, cleft, or juncture. [ 1913 Webster ]

2. (Anat. & Zool.) (a) The point of union between two parts, as the angles of the lips or eyelids, the mandibles of a bird, etc. (b) A collection of fibers connecting parts of the brain or spinal marrow; a chiasma. [ 1913 Webster ]

3. (Bot.) The line of junction or cohering face of two carpels, as in the parsnip, caraway, etc. [ 1913 Webster ]