<p><strong>Adjective</strong></p><ul><li>connecting two nonadjacent angles or vertices of a polygon or polyhedron, as a straight line</li><li>extending from one edge of a solid figure to an opposite edge, as a plane</li><li>having an oblique direction</li><li>having oblique lines, ridges, markings, etc.</li></ul><p><strong>Noun</strong></p><ul><li>a diagonal line or plane</li><li>virgule</li><li>a diagonal row, part, pattern, etc.</li><li>Manège (of a horse at a trot) the foreleg and the hind leg, diagonally opposite, which move forward simultaneously</li><li>diagonal cloth</li><li>a set of entries in a square matrix running either from upper left to lower right (main diagonal or principal diagonal) or lower left to upper right (secondary diagonal)</li><li>one of the oblique lines of squares on a chessboard</li></ul>