rational definition | Dictionary.com

Synonyms

Nearby Entries

rational - 9 dictionary results

ra⋅tion⋅al

[rash-uh-nl, rash-nl]

Use rational in a Sentence

–adjective

1.	agreeable to reason; reasonable; sensible: a rational plan for economic development.

2.	having or exercising reason, sound judgment, or good sense: a calm and rational negotiator.

3.	being in or characterized by full possession of one's reason; sane; lucid: The patient appeared perfectly rational.

4.	endowed with the faculty of reason: rational beings.

5.	of, pertaining to, or constituting reasoning powers: the rational faculty.

6.	proceeding or derived from reason or based on reasoning: a rational explanation.

Mathematics.

a.	capable of being expressed exactly by a ratio of two integers.

b.	(of a function) capable of being expressed exactly by a ratio of two polynomials.

8.	Classical Prosody. capable of measurement in terms of the metrical unit or mora.

–noun

9.	Mathematics. rational number.

Origin:
1350–1400; ME racional < L ratiōnālis, equiv. to ratiōn- (s. of ratiō) reason + -ālis -al ¹

Related forms:

ra⋅tion⋅al⋅ly, adverb

ra⋅tion⋅al⋅ness, noun

Synonyms:
2. intelligent, wise, judicious, sagacious, enlightened. 6. See reasonable.

Antonyms:
2. stupid. 3. insane.

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.
Cite This Source

Link To rational

ra·tion·al (rāsh'ə-nəl)

adj.

Having or exercising the ability to reason.
Of sound mind; sane.
Consistent with or based on reason; logical: rational behavior. See Synonyms at logical.
Mathematics Capable of being expressed as a quotient of integers.

n. Mathematics
A rational number.

[Middle English racional, from Old French racionel, from Latin ratiōnālis, from ratiō, ratiōn-, reason; see reason.]
ra'tion·al·ly adv., ra'tion·al·ness n.

The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source

Rational

Ra"tion*al\, a. [L. rationalis: cf. F. rationnel. See Ratio, Reason, and cf. Rationale.]

1. Relating to reason; not physical; mental.

Moral philosophy was his chiefest end; for the rational, the natural, and mathematics . . . were but simple pastimes in comparison of the other. --Sir T. North.

2. Having reason, or the faculty of reasoning; endowed with reason or understanding; reasoning.

It is our glory and happiness to have a rational nature. --Law.

3. Agreeable to reason; not absurd, preposterous, extravagant, foolish, fanciful, or the like; wise; judicious; as, rational conduct; a rational man.

4. (Chem.) Expressing the type, structure, relations, and reactions of a compound; graphic; -- said of formul[ae]. See under Formula.

Rational horizon. (Astron.) See Horizon, 2 (b) .

Rational quantity (Alg.), one that can be expressed without the use of a radical sign, or in extract parts of unity; -- opposed to irrational or radical quantity.

Rational symptom (Med.), one elicited by the statements of the patient himself and not as the result of a physical examination.

Syn: Sane; sound; intelligent; reasonable; sensible; wise; discreet; judicious.

Usage: Rational, reasonable. Rational has reference to reason as a faculty of the mind, and is opposed to traditional; as, a rational being, a rational state of mind, rational views, etc. In these cases the speculative reason is more particularly, referred to. Reasonable has reference to the exercise of this faculty for practical purposes, and means, governed or directed by reason; as, reasonable prospect of success.

What higher in her society thou find'st Attractive, human, rational, love still. --Milton.

A law may be reasonable in itself, although a man does not allow it, or does not know the reason of the lawgivers. --Swift.

Rational

Ra"tion*al\, n. A rational being. --Young.

Language Translation for : rational

Spanish: racional,

German: vernunftbegabt,

Japanese: 理性を持った

More Translations »

rational

1398, "endowed with reason," from L. rationalis "of or belonging to reason, reasonable," from ratio (gen. rationis) "reckoning, calculation, reason" (see ratio). Rationalist "physician whose treatment is based on reason" is from 1626; applied to a philosophical doctrine 1647. Rationalize is first recorded 1803, "to explain, to make reasonable;" in the psychological sense of "to give an explanation that conceals true motives" it dates from 1922.

Main Entry: ra·tio·nal
Pronunciation: 'ra-sh&-n&l
Function: adjective
1 : having reason or understanding
2 : relating to, based on, or guided by reason, principle, fairness, logic, a legitimate state interest, or a consideration of fact rational relationship to a legitimate state interest —In re J. M., 642 Atlantic Reporter, Second Series 1062 (1994)> —ra·tio·nal·i·ty /"ra-sh&-'na-l&-tE/ noun —ra·tio·nal·ly adverb

Main Entry: ra·tio·nal
Pronunciation: 'rash-n&l, -&n-^&l
Function: adjective
1 a : having reason or understanding b : relating to, based on, or agreeable to reason rational explanation> <rational behavior>
2 : using medical treatments based onreason or general principles —used especially of an ancient school of physicians; —compare EMPIRICAL 1a —ra·tio·nal·ly /-E/ adverb

rational ra·tion·al (rāsh'ə-nəl)
adj.

Having or exercising the ability to reason.
Influenced by reasoning rather than by emotion.
Of sound mind; sane.
Based on scientific knowledge or theory rather than practical observation.

rational
[Mathematics] a fractional number n/d, where n and d are integers, n is the numerator and d is the denominator. The set of all rational numbers is usually called Q. Computers do not usually deal with rational numbers but instead convert them to real numbers which are represented (approximately in some cases) as floating-point numbers. Compare irrational.

Search another word or see rational on Thesaurus | Reference

About · Privacy Policy · Terms of Use · Advertise with Us · Link to Us · NASCAR® · Contact Us