See Also: rational(dictionary)
rational(3)(dictionary)
rational(medicine)
rational(2)(dictionary)
rational(1)(dictionary)
Rational Basis(law)
rational psychology(encyclopedia)
rational number(encyclopedia)
Rational expectations(finance)
Rational expectations(money)

rational(1) (iou)



rational adjective. LME.
[Latin rationalis, formed as RATIO noun: see -AL1.]
Having the faculty of reasoning; endowed with reason. LME.
J. Plamenatz Man as a self-conscious, rational..being who can make choices.
b. Hist. Designating (any of) an ancient class of physicians, who deduced their treatment of cases from general principles. Formerly also, (of a field of study, esp. psychology) employing or based on deduction from general principles. M16.
c. Using the faculty of reasoning; having sound judgement; sensible, sane. M17.
P. Lively What had got into Helen, normally as rational as himself.
Of, pertaining to, or based on reason or reasoning. LME.
A. Cross That..is such nonsense. I refuse to pay it the compliment of rational refutation. G. Sayer Jack often experienced a conflict between his intuitive and rational sides.
b. Existing (only) in the mind, not real. Only in 17.
Grammar. Of a conjunction: expressing a reason for a statement. LME-L17.
a. Math. (Of a number, quantity, etc.) expressible as a ratio of integers; (of an expression etc.) including no radical quantities which cannot be reduced to such a ratio. L16.
b. Physics. Of electrical units and equations: rationalized (see RATIONALIZE verb 2b). L19.
In accordance with reason; not foolish, absurd, or extreme. M17.
A. S. Neill In Australia, fear of a spider is rational, for a spider can be death-dealing.
Special collocations: rational dress Hist. a style of women's dress of the late 19th cent., characterized by the wearing of bloomers or knickerbockers. rational horizon: see HORIZON noun 3. rational mechanics: as deduced logically from first principles.
rationally adverb E17.
rationalness noun (now rare) M17.