Commissure

Part of speech: noun (n.)

1. A joint, seam, or closure; the place where two bodies, or parts of a body, meet and unite; an interstice, cleft, or juncture.

2. The point of union between two parts, as the angles of the lips or eyelids, the mandibles of a bird, etc.

3. A collection of fibers connecting parts of the brain or spinal marrow; a chiasma.

4. The line of junction or cohering face of two carpels, as in the parsnip, caraway, etc.