You’re using an overly narrow sense of the term in math.
Consider any orthogonal coordinate system (https://en.wikipedia.org/wiki/Orthogonal_coordinates). The whole point of orthogonality in this case is that it makes coordinate values independent of each other - varying only one coordinate cannot result in a change in any other coordinate. The term is used in this same sense in many other areas of math, and elsewhere. This is the sense in which it’s been used in software, for more than half a century.
Forgive my curiosity, but in what sense were you “originally from math” but aren’t familiar with this term beyond a high school level understanding of geometry?
Your links barely prove anything? I already knew that statistics is a fictional field.