Part 393

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.

Pol`y*go*na"ceous (?), a. [See Polygonum.] (Bot.) Of or pertaining to a natural order of apetalous plants (PolygonaceÊ), 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.

Po*lyg"o*nal (?), a. Having many angles.

Polygonal numbers, certain figurate numbers. See under Figurate.

Pol`y*go*neu"tic (?), a. [Poly- + Gr. &?; offspring.] (Zoˆl.) Having two or more broods in a season.

Pol`y*go*nom"e*try (?), n. [Polygon + -metry.] The doctrine of polygons; an extension of some of the principles of trigonometry to the case of polygons.

Po*lyg"o*nous (?), a. Polygonal.

||Po*lyg"o*num (?), n. [NL., fr. Gr. &?; 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.

Po*lyg"o*ny (?), n. (Bot.) Any plant of the genus Polygonum.

||Pol`y*gor"di*us (?), n. [NL. See Poly-, and Gordius.] (Zoˆl.) A genus ||of marine annelids, believed to be an ancient or ancestral type. It ||is remarkable for its simplicity of structure and want of parapodia. ||It is the type of the order Archiannelida, or Gymnotoma. See Loeven's ||larva.

Pol"y*gram (?), n. [Gr. &?; marked with many stripes; poly`s many + &?; a line.] A figure consisting of many lines. [R.] Barlow.

Pol"y*graph (?), n. [Gr. &?; writing much; poly`s much, many + &?; to write: cf. F. polygraphe.] 1. An instrument for multiplying copies of a writing; a manifold writer; a copying machine.

2. In bibliography, a collection of different works, either by one or several authors. Brande & C.

{ Pol`y*graph"ic (?), Pol`y*graph"ic*al (?), } a. [Cf. F. polygraphique.] Pertaining to, or employed in, polygraphy; as, a polygraphic instrument.

2. Done with a polygraph; as, a polygraphic copy.

Po*lyg"ra*phy (?), n. [Gr. &?;; poly`s much + gra`fein to write: cf. F. polygraphie.] 1. Much writing; writing of many books. [Obs.] Fuller.

2. The art of writing in various ciphers, and of deciphering the same. [R.]

3. The art or practice of using a polygraph.

Pol"y*grooved` (?), a. [Poly- + groove.] Having many grooves; as, a polygrooved rifle or gun (referring to the rifling).

Pol"y*gyn (?), n. [Cf. F. polygyne. See Polygyny.] (Bot.) A plant of the order Polygynia.

||Pol`y*gyn"i*a (?), n. pl. [NL. See Polygyny.] (Bot.) A LinnÊan order ||of plants having many styles.

{ Pol`y*gyn"i*an (?), Po*lyg"y*nous (?), } a. (Bot.) Having many styles; belonging to the order Polygynia.

Po*lyg"y*nist (?), n. One who practices or advocates polygyny. H. Spenser.

Po*lyg"y*ny (?), n. [Poly- + Gr. &?; woman, wife.] The state or practice of having several wives at the same time; marriage to several wives. H. Spenser.

Pol`y*ha"lite (?), n. [Poly- + Gr. &?; salt.] (Min.) A mineral usually occurring in fibrous masses, of a brick-red color, being tinged with iron, and consisting chiefly of the sulphates of lime, magnesia, and soda.

{ Pol`y*he"dral (?), Pol`y*hed"ric*al (?), } a. [See Polyhedron.] (Geom.) Having many sides, as a solid body.

Polyhedral angle, an angle bounded by three or more plane angles having a common vertex.

Pol`y*he"dron (?), n.; pl. E. Polyhedrons. (#), L. Polyhedra (#). [NL., fr. Gr. &?; with many seats or sides; poly`s many + &?; a seat or side: cf. F. polyËdre.] 1. (Geom.) A body or solid contained by many sides or planes.