n. 1. A line or place at which two things are joined. 2. Anatomy a. A tract of nerve fibers passing from one side to the other of the spinal cord or brain. b. The point or surface where two parts, such as the eyelids, lips, or cardiac valves, join or form a connection. 3. Botany The surface or place along which two structures, such as carpels, are joined. [Middle English, from Latin commissūra, from commissus, past participle of committere, to join; see COMMIT.] com′mis·sural adj. |
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