fissure(redirected from anal fissure, fissure in ano)
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1. Anatomy a narrow split or groove that divides an organ such as the brain, lung, or liver into lobes
2. a small unnatural crack in the skin or mucous membrane, as between the toes or at the anus
3. a minute crack in the surface of a tooth, caused by imperfect joining of enamel during development
A high, narrow cave passageway.
An extensive crack in a rock.
A small cracklike discontinuity with a slight opening or displacement of the fracture surfaces.