- connecting two nonadjacent angles or vertices of a polygon or polyhedron, as a straight line.
- extending from one edge of a solid figure to an opposite edge, as a plane.
- diagnostic specificity,
- diagnostic ultrasound,
- diagonal cloth,
- diagonal conjugate,
- diagonal matrix,
- diagonal process,
Origin of diagonal
Examples from the Web for diagonally
Place these Nine in a Square of three, they will directly and diagonally make 18.The History of the Devil|Daniel Defoe
On the opposite corner, diagonally, have an imitation stump with hatchet sticking in the wood.Dinners and Luncheons|Paul Pierce
The red letters of "Votes for Women" ran around her diagonally like the stripes of a barber-pole.Affinities and Other Stories|Mary Roberts Rinehard
Diagonally across it, many yards away, ran one of the stone fences of the region, a long dike of loosely piled and rounded rock.The Long Roll|Mary Johnston
Diagonally across from your house, in the corner house; in my window, in a cage, is a canary.Delusion and Dream|Wilhelm Jensen
Word Origin for diagonal
1540s (implied in diagonally), from Middle French diagonal, from Latin diagonalis, from diagonus "slanting line," from Greek diagonios "from angle to angle," from dia- "across" (see dia-) + gonia "angle," related to gony "knee" (see knee (n.)). As a noun, from 1570s.