- a narrow opening produced by cleavage or separation of parts.
- cleavage (def. 1).
- a natural division or groove in an organ, as in the brain.
- to make fissures in; cleave; split.
- to open in fissures; become split.
- any long narrow cleft or crack, esp in a rock
- a weakness or flaw indicating impending disruption or discord
- a narrow split or groove that divides an organ such as the brain, lung, or liver into lobes
- a small unnatural crack in the skin or mucous membrane, as between the toes or at the anus
- a minute crack in the surface of a tooth, caused by imperfect joining of enamel during development
- to crack or split apart
