Definition of "fissure"

fissure

/ˈfɪʃ.ə/

noun
plural fissures
1. A long, narrow crack or opening made by breaking or splitting, especially in rock or earth.
  Quotations
  After Miller's Dale Junction, the main Derby-Manchester line crosses the Wye for the last time and turns north-west up Great Rocks Dale, a natural fissure several miles long.
  1960 April, J. P. Wilson, E. N. C. Haywood, “The route through the Peak—Derby to Manchester: Part Two”, in Trains Illustrated, page 224
2. (anatomy) A groove, deep furrow, elongated cleft or tear between body parts or in the substance of an organ; a sulcus.
3. (anatomy) A break or slit in tissue usually at the junction of skin and mucous membrane.
4. A state of incompatibility or disagreement.
verb
third-person singular simple present fissures, present participle fissuring, simple past and past participle fissured
1. To split, forming fissures.