squill, common name for two genera of Old World bulbous plants of the family Liliaceae (
lily family). The horticulturists' squill is any plant of the genus
Scilla, mostly spring-blooming low herbs with commonly deep blue but also white, rose, or purplish flowers borne along a leafless stem; the leaves are usually narrow. Species of
Scilla are naturalized and used in rock gardens and borders; of these, the Siberian squill (
S. sibirica) has long been a rock-garden favorite. The wood, or wild, hyacinth, called also bluebell or harebell (
S. nonscripta), is the common squill. The pharmacists' squill, or sea onion (
Urginea maritima), produces whitish or rose flowers in the autumn before it produces leaves. Its bulbs, collected chiefly from the Mediterranean region, are sold as white or red squill-the white is a drug used as a diuretic, stimulant, and expectorant; the red is used mostly as a rat poison. Squill is classified in the division
Magnoliophyta, class Liliopsida, order Liliales, family Liliaceae.