incision (n.)

late 14c., "a cutting made in surgery," from Old French incision (13c.) and directly from Latin incisionem (nominative incisio) "a cutting into," recorded only in figurative senses, noun of action from past participle stem of incidere "to cut in," from in- "into, in, on, upon" (from PIE root *en "in") + -cidere, combining form of caedere "to cut" (from PIE root *kae-id- "to strike"). Meaning "act of cutting into" is from early 15c.