[uh-lis-uh
m] 
| 1. | any of various plants belonging to the genus Alyssum, of the mustard family, having clusters of small yellow or white flowers. |
| 2. | any of several related plants of the genus Aurinia, as A. saxatilis, a widely cultivated species with yellow flowers. |
| 3. | sweet alyssum. |
| a·lys·sum (ə-lĭs'əm) n.
[New Latin Alyssum, genus name, from Latin alysson, kind of madder, from Greek alusson, a plant believed to cure rabies : a-, not; see a-1 + lussa, rabies; see w  kwo- in Indo-European roots.] |
| hoary alyssum n. 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. |
| sweet alyssum n. A widely cultivated annual or perennial herb (Lobularia maritima) of the mustard family, native to the Mediterranean region, having racemes of long-lasting flowers varying in size and color. Also called alyssum. |