1. quadrilateral - Noun
2. quadrilateral - Adjective
3. quadrilateral - Adjective Satellite
Having four sides, and consequently four angles; quadrangular.
A plane figure having four sides, and consequently four angles; a quadrangular figure; any figure formed by four lines.
An area defended by four fortresses supporting each other; as, the Venetian quadrilateral, comprising Mantua, Peschiera, Verona, and Legnano.
Source: Webster's dictionaryA convex quadrilateral is cyclic if and only if opposite angles sum to 180°. Source: Internet
A flag is a piece of fabric (most often rectangular or quadrilateral) with a distinctive design that is used as a symbol, as a signaling device, or as decoration. Source: Internet
Alternative definitions are a quadrilateral with an axis of symmetry bisecting one pair of opposite sides, or a trapezoid with diagonals of equal length. Source: Internet
All four subway lines cross downtown, forming a quadrilateral configuration, and the Orange and Green Lines (which run approximately parallel in that district) also connect directly at two stations just north of downtown. Source: Internet
A part of that definition may be singled out (using parentheses here): * a square : ( a quadrilateral that has interior angles which are all right angles ), and that has bounding sides which all have the same length. Source: Internet
A quadrilateral is a square if and only if it is both a rhombus and a rectangle (four equal sides and four equal angles). Source: Internet