(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
an oblique line of squares of the same color on a checkerboard; "the bishop moves on the diagonals"
a line or cut across a fabric that is not at right angles to a side of the fabric
(geometry) a straight line connecting any two vertices of a polygon that are not adjacent
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"
a detailed plan or explanation to guide you in setting standards or determining a course of action; "the president said he had a road map for normalizing relations with Vietnam"
(meteorology) rapid inward circulation of air masses about a low-pressure center; circling counterclockwise in the northern hemisphere and clockwise in the southern
a defensive post at the end of a bridge nearest to the enemy
an area in hostile territory that has been captured and is held awaiting further troops and supplies; "an attempt to secure a bridgehead behind enemy lines"; "the only foothold left for British troops in Europe was Gibraltar"
an initial accomplishment that opens the way for further developments; "the town became a beachhead in the campaign to ban smoking outdoors"; "they are presently attempting to gain a foothold in the Russian market"
a bridgehead on the enemy's shoreline seized by an amphibious operation; "the Germans were desperately trying to contain the Anzio beachhead"
an electric railway operating below the surface of the ground (usually in a city); "in Paris the subway system is called the `metro' and in London it is called the `tube' or the `underground'"