Longman Dictionary of Contemporary English
The Collaborative International Dictionary
Diametrically \Di*am"e*tric*al*ly\, adv. In a diametrical manner; directly; as, diametrically opposite.
Whose principles were diametrically opposed to his.
--Macaulay.
Douglas Harper's Etymology Dictionary
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.
Wiktionary
adv. 1 Separated by a diameter, on exactly the opposite side. 2 (context Frequently used in the phrase ''diametrically opposed'' English) absolutely (in opposition).
WordNet
adv. as from opposite ends of a diameter; "when two honest witnesses give accounts of the same event that differ diametrically, how can anyone prove that the evidence you gave was deliberately false?"; "three of these brushes were approximately 120 feet apart and the fourth diametrically opposite to one of the three"
Usage examples of "diametrically".
So the sixteenth century classed together as Anabaptists men with not only divergent but with diametrically opposite views on the most vital questions.
Then, too, the Matter of the realm of process ceaselessly changes its form: in the eternal, Matter is immutably one and the same, so that the two are diametrically opposites.
Both parties were on the move when they met, travelling in diametrically opposite directions, but the dark landers were ready enough to stop and talk and Hyry Keshvara was still enthusiastic to find guides willing to escort the princess and herself to the ford where she hoped to meet Carus Fraxinus and his party.
I think no better evidence of this can be required than that the two most experienced observers who have ever lived, namely, Kolreuter and Gartner, should have arrived at diametrically opposite conclusions in regard to the very same species.
I followed my research in hypnology until I came to the point where the mass of facts I had accumulated trapped me in a jungle of various diametrically opposed conclusions, many of which verged upon the occult.
Since, as was said, the affections of heaven and the lusts of hell are diametrically opposite to each other, plainly a heavenly joy is so unenjoyable to hell that it is unbearable, and in turn an infernal joy is so unenjoyable to heaven that it is unbearable, too.
Although professing diametrically opposite principles from those of the editor of the other paper, Beauchamp -- as it sometimes, we may say often, happens -- was his intimate friend.
And after the adjutant comes the commissary general asking where the stores are to be taken, and the chief of the hospitals asks where the wounded are to go, and a courier from Petersburg brings a letter from the sovereign which does not admit of the possibility of abandoning Moscow, and the commander in chief's rival, the man who is undermining him (and there are always not merely one but several such), presents a new project diametrically opposed to that of turning to the Kaluga road, and the commander in chief himself needs sleep and refreshment to maintain his .
The sterility is of all degrees, and is often so slight that the two most careful experimentalists who have ever lived, have come to diametrically opposite conclusions in ranking forms by this test.
Here was Yage, a captain of many years' experience from a diametrically opposed military force, and he was expecting her to hand over to him the explanation of why she intended to defy a direct order.
At this point I shall mention just one example, a behavior that at first seems diametrically opposed to evolutionary logic: sexual cannibalism.
Soon afterward it was followed by the far larger bulk of the half-mile-square Radiator Assembly projecting from Detroit diametrically opposite the solar dish, which passed them edge-on and extended away beyond the limit of the window’.