What word or phrase does your mother always say?
c.1400, from Old French fissure (13c.) and directly from Latin fissura "a cleft," from root of findere "to split, cleave," from PIE *bhi-n-d-, from root *bheid- "to split" (cf. Sanskrit bhinadmi "I cleave," Old High German bizzan "to bite," Old English bita "a piece bitten off, morsel," Old Norse beita "to hunt with dogs," beita "pasture, food").
fissure fis·sure (fĭsh'ər)
A deep furrow, cleft, or slit.
A developmental break or fault in the enamel of a tooth.