sea onion

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The squill Urginea maritima, whose bulb yields a powder used as a rat poison and formerly used medicinally.
• noun Any of various similar bulbous plants.

from the GNU version of the Collaborative International Dictionary of English.

• (Bot.) The officinal squill. See squill.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Drimia maritima, the sea squill.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun having dense spikes of small white flowers and yielding a bulb with medicinal properties
• noun European scilla with small blue or purple flowers