commissure

commissure \KOM-uh-shoor, -shur\, noun:

1. a joint; seam; suture.
2. Botany. the joint or face by which one carpel coheres with another.
3. Anatomy, Zoology. a connecting band of nerve fiber, especially one joining the right and left sides of the brain or spinal cord.

See the thick middle commissure joining the two thalami, just as the corpus callosum and fornix join the hemispheres.
-- William James, "The Structure of the Brain," Writings, 1878-1899

By day the shepherd would have raised his pipe in vain, towards the long clear cut commissure of earth and sky.
-- Samuel Beckett, Molloy, 1955

Though his solution to the problem isn't the universal solvent he leads the reader to expect, his project is still a neat example of that modern commissure where Continental theory and analytic practice fuse.
-- David Foster Wallace, "Greatly Exaggerated," A Supposedly Fun Thing I'll Never Do Again, 1997

Commissure stems from the Latin word committere meaning logically "to commit."