calendula n 1: any of numerous chiefly annual herbs of the genus Calendula widely cultivated for their yellow or orange flowers; often used for medicinal and culinary purposes
Calendula \Ca*len"du*la\, n. [NL., fr. L. calendae calends.] (Bot.) A genus of composite herbaceous plants. One species, {Calendula officinalis}, is the common marigold, and was supposed to blossom on the calends of every month, whence the name. [1913 Webster]