{ } a. 1. Of or pertaining to a diameter. [ 1913 Webster ]
2. As remote as possible, as if at the opposite end of a diameter; directly adverse. [ 1913 Webster ]
adv. In a diametrical manner; directly; as, diametrically opposite. [ 1913 Webster ]
Whose principles were diametrically opposed to his. Macaulay. [ 1913 Webster ]