Definitions for "Orthogonal"
Right-angled; rectangular; as, an orthogonal intersection of one curve with another.
the word ortho means right angles; ogonias means joints.
Two planes that are at right angles to each other are said to be orthogonal.
not pertinent to the matter under consideration; "an issue extraneous to the debate"; "the price was immaterial"; "mentioned several impertinent facts before finally coming to the point"
statistically unrelated
Orthogonal variables are completely unrelated. They are independent. Changes in one have no effect on the other.
Term used to signify that two signals (or signal attributes) are mutually transparent and non-interfering with each other. Frequency and amplitude modulation are orthogonal signal attributes.
Popular layout and drawing style. Nodes are usually represented by rectangles, edges are made up of alternating vertical and horizontal segments.
Keywords:  matrix, columns, basis, form
A matrix is orthogonal if AT A = I. The columns of such a matrix form an orthogonal basis.