■ adjective
1》 based on or in accordance with reason or logic.
2》 able to think sensibly or logically.
3》 having the capacity to reason.
4》 Mathematics (of a number, quantity, or expression) expressible, or containing quantities which are expressible, as a ratio of whole numbers.
Derivatives
~ity noun
~ly adverb
Origin
ME: from L. ~is , from ratio(n-) (see ratio ).