n, pl  lil*ies of the valley  1  :  an erect low-growing perennial herb of the genus Convallaria (C. majalis) that has two large oblong lanceolate leaves and a raceme of fragrant nodding bell-shaped white flowers and is the source of convallaria, convallamarin, convallarin, and convallatoxin  2  :  the dried rhizome and roots of the lily of the valley used as a cardiac tonic .
 
 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2024.