‖n. [ NL., fr. Gr. &unr_; a kind of plant; poly`s many + go`ny the knee, a joint of a plant. So called in allusion to the numerous joints. ] (Bot.) A genus of plants embracing a large number of species, including bistort, knotweed, smartweed, etc. [ 1913 Webster ]

n. [ Gr. poly`gwnos polygonal; poly`s many + gwni`a angle: cf. F. polygone. ] (Geom.) A plane figure having many angles, and consequently many sides; esp., one whose perimeter consists of more than four sides; any figure having many angles. [ 1913 Webster ]

Polygon of forces (Mech.), a polygonal figure, the sides of which, taken successively, represent, in length and direction, several forces acting simultaneously upon one point, so that the side necessary to complete the figure represents the resultant of those forces. Cf. Parallelogram of forces, under Parallelogram. [ 1913 Webster ]

a. [ See Polygonum. ] (Bot.) Of or pertaining to a natural order of apetalous plants (Polygonaceæ), of which the knotweeds (species of Polygonum) are the type, and which includes also the docks (Rumex), the buckwheat, rhubarb, sea grape (Coccoloba), and several other genera. [ 1913 Webster ]

a. Having many angles. [ 1913 Webster ]

Polygonal numbers, certain figurate numbers. See under Figurate. [ 1913 Webster ]

a. [ Poly- + Gr. &unr_; offspring. ] (Zool.) Having two or more broods in a season. [ 1913 Webster ]

n. [ Polygon + -metry. ] The doctrine of polygons; an extension of some of the principles of trigonometry to the case of polygons. [ 1913 Webster ]

a. Polygonal. [ 1913 Webster ]

n. (Bot.) Any plant of the genus Polygonum. [ 1913 Webster ]