polygonum

Etymology From translingual Polygonum, from Ancient Greek πολύγονον (polúgonon, “knotweed”), from πολύς (polús, “many”) + γόνυ (gónu, “knee”), so called in allusion to the numerous joints, or neuter of πολύγονος (polúgonos, “prolific”), from πολύς (polús, “many”) + γόνος (gónos, “offspring”). If the former of those two hypotheses is true, then the word would be related to polygon (from γωνία (gōnía, “corner, angle”), a derivative of γόνυ (gónu)).