pluralcosmos\-məs, -məz\alsocos·mos·es\-mə-səz\[New Latin, genus name, from Greek kosmos]: any of a genus (Cosmos) of tropical American composite herbs; especially: a widely cultivated tall annual (C. bipinnatus) with yellow or red disks and showy ray flowers
Any of the garden plants that make up the genus Cosmos in the aster family (Asteraceae), containing about 25 species native to the tropical New World. Heads of flowers are borne along long flower stalks or together in an open cluster. The disk flowers are red or yellow; the ray flowers, sometimes notched, may be white, pink, red, purple, or other colors. Most annual ornamental varieties have been developed from the common garden cosmos (C. bipinnatus).