any of a genus (Euphrasia) of plants of the figwort family, esp. a small plant (E. americana) of NE U.S. having pale lavender flowers in leafy clusters: formerly used in treating eye disorders
See eyebright in American Heritage Dictionary 4
(īˈbrītˌ)
noun
Any of several plants of the genus Euphrasia, having small, opposite, toothed leaves and white and purplish flowers grouped in spikes.