Translated literally from the Greek “orthogōnios,” which means “right-angled,” the adjective “orthogonal” relates to anything having to do with right angles. In the most basic sense, that means objects that have right angles or that intersect at right angles, but it’s also used in mathematics for slopes and curves with tangents that have orthogonal intersections. In statistics, “orthogonal” is used to refer to variables that are independent of each other.