[noun] (geometry) a straight line connecting any two vertices of a polygon that are not adjacent
[noun] a line or cut across a fabric that is not at right angles to a side of the fabric Synonyms:bias
[noun] an oblique line of squares of the same color on a checkerboard; "the bishop moves on the diagonals"
[noun] (mathematics) a set of entries in a square matrix running diagonally either from the upper left to lower right entry or running from the upper right to lower left entry
[adjective] at an angle; especially connecting two nonadjacent corners of a plane figure or any two corners of a solid that are not in the same face; "a diagonal line across the page"