To cut asunder; cleave; split; rend; sever.To cut lengthwise or into long pieces or strips: as, the gale has slit the sails into ribbons.To cut or make a long fissure in; slash.n. A long cut or rent; a narrow opening.n. A pocket.n. A cleft or crack in the breast of fat cattle.n. In coal-mining, a short heading connecting two other headings.n. Specifically, in zoöl., anat., and embryology, a visceral cleft; one of the series of paired (right and left) openings in the front and sides of the head and neck of every vertebrate embryo, some of which or all may disappear, or some of which may persist as gill-slits or their equivalents; a branchial, pharyngeal, etc., slit.n. A Middle English contracted form of slideth, third person singular present indicative of slide.n. In optics, the narrow opening through which a beam of light is admitted into the tube of a spectroscope or other optical instrument.