The degree of perpendicularity, or squareness, between the two axes in an X-Y or X-Z table This parameter is usually measured in arc-seconds or microradians.

the relation of opposition between things at right angles

the quality of lying or intersecting at right angles

The degree to which stages are aligned with their motion at right angles to one another. Motion of an X-Y system is typically 90° apart in a single plane. X-Y-Z systems are all mutually at a 90° relationship in a 3D space. The specification is typically the angle measured between the best-fit-straight-line of X-axis motion and the best-fit-straight-line of Y-axis motion.

the measure of perpendicularity between the X- and Y-axis geometries printed on a substrate.

In mathematics, orthogonal is synonymous with perpendicular when used as a simple adjective that is not part of any longer phrase with a standard definition. It means at right angles. It comes from the Greek orthos, meaning "straight", used by Euclid to mean right; and gonia, meaning angle.