commissure

Concise Oxford English Dictionary © 2008 Oxford University Press:
commissure /ˈkɒmɪsjʊə/

▶noun Anatomy

• 1 the joint between two bones.

• 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.

– derivatives
commissural /ˌkɒmɪˈsjʊər(ə)l/ adjective.

– origin ME: from L. commissura ‘junction’, from committere (see commit).