embolism (n.)

late 14c., "intercalation, insertion of days into a calendar," from Old French embolisme "intercalation," from Late Latin embolismus "insertion of days in a calendar to correct errors," from Late Greek embolismos "intercalation," from embolos "peg, stopper; anything pointed so as to be easily thrust in," also "a tongue (of land), beak (of a ship)," from emballein "to insert, throw in, invade" from assimilated form of en "in" (see en- (2)) + ballein "to throw" (from PIE root *gwele- "to throw, reach," with extended sense "to pierce"). Medical sense of "obstruction of a blood vessel" is first recorded in English 1855. Related: embolismic.