c. 1400, from Old French fissure (13c.) and directly from Latin fissura "a cleft," from root of findere "to split, cleave, separate, divide," from PIE *bhind-, nasalized form of root *bheid- "to split."
fishwife
fishy
fisk
fissile
fission
fissure
fist
fistful
fistiana
fistic
fisticuffs