diagonal

[dahy-ag-uh-nl, -ag-nl] /daɪˈæg ə nl, -ˈæg nl/
adjective
1.
Mathematics.
  1. connecting two nonadjacent angles or vertices of a polygon or polyhedron, as a straight line.
  2. extending from one edge of a solid figure to an opposite edge, as a plane.
2.
having an oblique direction.
3.
having oblique lines, ridges, markings, etc.
noun
4.
a diagonal line or plane.
5.
virgule.
6.
a diagonal row, part, pattern, etc.
7.
Manège. (of a horse at a trot) the foreleg and the hind leg, diagonally opposite, which move forward simultaneously.
8.
diagonal cloth.
9.
Mathematics. 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)
10.
Chess. one of the oblique lines of squares on a chessboard:
He advanced his bishop along the open diagonal.
Origin
1535-45; < Latin diagōnālis < Greek diagṓn(ios) from angle to angle (see dia-, -gon) + Latin -ālis -al1
Related forms
diagonally, adverb
nondiagonal, adjective, noun
nondiagonally, adverb
Examples from the web for diagonal
  • The bridge crosses above the lower end of the diagonal corridor.
  • All lines were straightened, so that the map consists entirely of horizontal, vertical or diagonal lines.
  • Draw a diagonal line to the opposite top corner of the box.
  • The diagonal is the sum of the two vectors that form the sides of the parallelogram.
  • Measure for equal diagonal dimensions to verify that the structure will be square.
  • As a fail-safe, he added straight, diagonal cables to stiffen the superstructure.
  • At such moments, a dancer crossing the stage on a diagonal created a sense of daring and excitement.
  • The adviser had drawn a perfectly straight diagonal line across each and every offending page.
  • The diagonal line is a diffraction spike produced by the telescope's optical system.
  • Then cut the tip at a diagonal and thread the tube through the hole.
British Dictionary definitions for diagonal

diagonal

/daɪˈæɡənəl/
adjective
1.
(maths) connecting any two vertices that in a polygon are not adjacent and in a polyhedron are not in the same face
2.
slanting; oblique
3.
marked with slanting lines or patterns
noun
4.
(maths) a diagonal line or plane
5.
(chess) any oblique row of squares of the same colour
6.
cloth marked or woven with slanting lines or patterns
7.
something put, set, or drawn obliquely
8.
another name for solidus (sense 1)
9.
one front leg and the hind leg on the opposite side of a horse, which are on the ground together when the horse is trotting
Derived Forms
diagonally, adverb
Word Origin
C16: from Latin diagōnālis, from Greek diagōnios, from dia- + gōnia angle
Word Origin and History for diagonal
adj.

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.

diagonal in Science
diagonal
  (dī-āg'ə-nəl)   
Adjective  Connecting two nonadjacent corners in a polygon or two nonadjacent corners in a polyhedron that do not lie in the same face.

Noun  A diagonal line segment.