commisure

Noun

commissure (plural commissures)

1. The joint between two bones.
   • ...that round about the commissure of all our joints...1734, William Stukeley, Of the Gout, J. Roberts, page 14
2. A band of nerve tissue connecting the hemispheres of the brain, the two sides of the spinal cord, etc.
3. The line where the upper and lower lips or eyelids meet.
   • There is a third inner eyelid, highly developed and of beautiful mechanism: this is the nictitating membrane, or "winker" (nictito, I wink), a delicate, elastic, translucent, pearly-white fold of the conjunctiva. While the other lids move vertically and have a horizontal commissure, the winker...1884, Elliott Coues, “§ 4.—An Introduction to the Anatomy of Birds.”, in Key to North American Birds. […], 2nd edition, Boston, Mass.: Estes and Lauriat, →OCLC, part II (General Ornithology), page 180