poin·set·ti·a / poinˈset(ē)ə/ • n. a small Mexican shrub (Euphorbia pulcherrima, formerly Poinsettia pulcherrima) of the spurge family, with large showy scarlet bracts surrounding the small yellow flowers, popular as a Christmas houseplant.

poinsettia Ornamental shrub, native to Mexico. It has tapering leaves and tiny yellow flowers centred in leaf-like red, white or pink bracts. It is a popular house plant. In its natural environment, the tree grows to c.5m (16ft). Height: to 60cm (2ft) when potted. Family Euphorbiaceae; species Euphorbia pulcherrima.

poinsettia XIX. f. name of J. R. Poinsett (d. 1851), Amer. minister to Mexico, discoverer of the plant; see -IA1.