Squill \Squill\, n. [F. squille (also scille a squill, in sense 1), L. squilla, scilla, Gr. ?.] 1. (Bot.) (a) A European bulbous liliaceous plant ({Urginea, formerly Scilla, maritima}), of acrid, expectorant, diuretic, and emetic properties used in medicine. Called also {sea onion}. (b) Any bulbous plant of the genus {Scilla}; as, the bluebell squill ({S. mutans}). 2. (Zo["o]l.) (a) A squilla. (b) A mantis.