any of several plants (esp. genus Hippeastrum) of the lily family bearing several white, purple, pink, or red flowers on a leafless stem, including the belladonna lily
See amaryllis in American Heritage Dictionary 4
(ămˌə-rĭlˈĭs)
noun
Any of several chiefly tropical American bulbous plants of the genus Hippeastrum grown as ornamentals for their large, showy, funnel-shaped, variously colored flowers that are grouped in umbels.