The American Heritage® Dictionary of the English Language, 4th Edition
n. See sweet alyssum.
n. Any of various chiefly Mediterranean weeds or ornamentals of the genus Alyssum in the mustard family, having racemes of white or yellow flowers. Also called madwort.
n. Any of several plants, of the genus Alyssum, that have racemes of white or yellow flowers.
Word Usage
"Provide a mixture of nectar and seed rich flowering plants such as alyssum, sunflower and knapweed, which will attract insects and also provide seed for birds to feed on."