er·i·og·o·num \ˌerēˈägənəm\noun Etymology: New Latin, from erio- + -gonum (from Greek gony knee); from the woolly stems of some species — more at knee 1.capitalized: a genus of No. American herbs (family Polygonaceae) with small clustered flowers subtended by an involucre 2.-s: any plant of the genus Eriogonum