— orthogonality , n. — orthogonally , adv.
/awr thog"euh nl/ , adj.
1. Math.
a. Also, orthographic . pertaining to or involving right angles or perpendiculars: an orthogonal projection.
b. (of a system of real functions) defined so that the integral of the product of any two different functions is zero.
c. (of a system of complex functions) defined so that the integral of the product of a function times the complex conjugate of any other function equals zero.
d. (of two vectors) having an inner product equal to zero.
e. (of a linear transformation) defined so that the length of a vector under the transformation equals the length of the original vector.
f. (of a square matrix) defined so that its product with its transpose results in the identity matrix.
2. Crystall. referable to a rectangular set of axes.
[ 1565-75; obs. orthogon ( ium ) right triangle ( orthogonium orthogónion (neut.) right-angled, equiv. to ortho- ORTHO- + -gonion -GON) + -AL 1 ]