/
dʌɪˈag(ə)n(ə)l/
adj.
denoting a straight line joining opposite corners of a rectangle, square, or other figure.
▸(of a line) straight and at an angle; slanting.
▸Mathematics denoting a matrix with non-zero elements only on the diagonal running from the upper left to the lower right.
n.
a diagonal line.
Derivative
Etymology
C16: from L. diagonalis, from Gk diagōnios ‘from angle to angle’, from dia ‘through’ + gōnia ‘angle’.