- of, relating to, or along a diameter.
- in direct opposition; being at opposite extremes; complete: diametrical opposites; a diametrical difference.
- completely; utterly (esp in the phrase diametrically opposed)
1630s, “completely” (opposed, contrary, etc.); see diametric. Mostly in figurative use; the two points that mark the ends of a line of diameter across a circle are opposite one another.