An annual European herb (Berteroa incana) of the mustard family, having silvery foliage, oblong fruits, and deeply notched white flowers. It is naturalized in eastern North America. Also called alyssum.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.