pentagon

• POS: Noun
• HYPHEN: Pen=ta=gon

CIDE DICTIONARY

pentagon, n. [Gr. penta`gwnon; penta- (see Penta-) + gwni`a angle: cf. L. pentagonium, F. pentagone.].

 A plane figure having five angles, and, consequently, five sides; any figure having five angles.  [1913 Webster]

Regular pentagon, a pentagon in which the angles are all equal, and the sides all equal.

OXFORD DICTIONARY

pentagon, n.
1 a plane figure with five sides and angles.
2 (the Pentagon) a the pentagonal Washington headquarters of the US defence forces. b the leaders of the US defence forces.

Derivative

pentagonal adj.

Etymology

F pentagone or f. LL pentagonus f. Gk pentagonon (as PENTA-, -GON)

ROGET THESAURUS

pentagon

Angularity

N angularity, angularness, aduncity, angle, cusp, bend, fold, notch, fork, bifurcation, elbow, knee, knuckle, ankle, groin, crotch, crutch, crane, fluke, scythe, sickle, zigzag, kimbo, akimbo, corner, nook, recess, niche, oriel, coign, right angle, obliquity, angle of 45 degrees, miter, acute angle, obtuse angle, salient angle, reentering angle, spherical angle, angular measurement, angular elevation, angular distance, angular velocity, trigonometry, goniometry, altimetry, clinometer, graphometer, goniometer, theodolite, sextant, quadrant, dichotomy, triangle, trigon, wedge, rectangle, square, lozenge, diamond, rhomb, rhombus, quadrangle, quadrilateral, parallelogram, quadrature, polygon, pentagon, hexagon, heptagon, octagon, oxygon, decagon, pyramid, cone, Platonic bodies, cube, rhomboid, tetrahedron, pentahedron, hexahedron, octahedron, dodecahedron, icosahedron, eicosahedron, prism, pyramid, parallelopiped, curb roof, gambrel roof, mansard roof, angular, bent, crooked, aduncous, uncinated, aquiline, jagged, serrated, falciform, falcated, furcated, forked, bifurcate, zigzag, furcular, hooked, dovetailed, knock kneed, crinkled, akimbo, kimbo, geniculated, oblique, fusiform, wedge-shaped, cuneiform, cuneate, multangular, oxygonal, triangular, trigonal, trilateral, quadrangular, quadrilateral, foursquare, rectangular, square, multilateral, polygonal, cubical, rhomboid, rhomboidal, pyramidal.