orthogonal

/ɔrˈθɑgənl/

Two lines that are orthogonal are perpendicular or intersecting at a right angle, like a t-square used by draftsmen.

The word orthogonal comes from the Greek orthogōnios meaning "right-angled." While this word is used to describe lines that meet at a right angle, it also describes events that are statistically independent, or do not affect one another in terms of outcome.

Definitions of orthogonal

1. adjective

   having a set of mutually perpendicular axes; meeting at right angles
   “wind and sea may displace the ship's center of gravity along three orthogonal axes”

   synonyms: rectangular

   perpendicular

   intersecting at or forming right angles
2. adjective

   not pertinent to the matter under consideration
   synonyms: extraneous, immaterial, impertinent

   irrelevant

   having no bearing on or connection with the subject at issue
3. adjective

   statistically unrelated
   synonyms:

   unrelated

   lacking a logical or causal relation