hy·dras·tis \hīˈdrastə̇s\noun Etymology: New Latin, probably irregular from hydr- 1.capitalized: a genus of herbs (family Ranunculaceae) having palmately lobed leaves and small greenish apetalous flowers — see goldenseal 2.-es: the dried rhizome and roots of the goldenseal (Hydrastis canadensis) formerly used in pharmacy as a bitter tonic