fish’ure.

A cleft; a narrow chasm made by the parting of any substance; a longitudinal opening; as the fissure of a rock.

In surgery, a crack or slit in a bone, either transversely or longitudinally, by means of external force.

In anatomy, a deep, narrow sulcus, or depression, dividing the anterior and middle lobes of the cerebrum on each side.

To cleave; to divide; to crack or fracture.