Incommensurable, a.
Etymology: [Pref. in- not + commensurable: cf. F. incommensurable.]
Not commensurable; having no common measure or standard of comparison; as, quantities are incommensurable when no third quantity can be found that is an aliquot part of both; the side and diagonal of a square are incommensurable with each other; the diameter and circumference of a circle are incommensurable. They are quantities incommensurable. Burke. -- In`com*men"su*ra*ble*ness, n. -- In`com*men"su*ra*bly, adv.
1 other Webster entry under this spelling
Incommensurable, n.
One of two or more quantities which have no common measure.
Shades of meaning
Fernald has no entry of its own for incommensurable; he lists it under incongruous.
Where he writes about it:
Incommensurable is a mathematical term, applying to two or more quantities that have no common measure or aliquot part. — from incongruous