rational

WOTD – 20 January 2009    

English

Alternative forms

• rationall (obsolete)

Pronunciation

• enPR: ră'sh(ə)nəl, IPA: /ˈræʃ(ə)nəl/, X-SAMPA: /"r{S(@)n@l/

• Audio (US)

  (file)

Etymology 1

From Old French rationel, rational, from Latin rationalis (“of or belonging to reason, rational, reasonable”), from ratio (“reason”)

Adjective

rational (comparative more rational, superlative most rational)

1. Capable of reasoning.
   • 2001, Mark Sainsbury, chapter 1, Logical Forms — An Introduction to Philosophical Logic, edition 2nd, Blackwell Publishing, ISBN 978-0-63121-679-7, §7, page 32:

     How could a valid argument ever be persuasive? It is possible because we do not always acknowledge or take explicit note of all the logical consequences of our beliefs. If we did explicitly hold before our minds all the logical consequences of our beliefs, seeing them as consequences, we would already have accepted the conclusion of any valid argument whose premises we have accepted. Hence no valid argument could be persuasive. This is how things would be with a perfectly rational being. The utility of valid arguments is a monument to our frailty: to the fact that we are not completely rational beings.

   Man is a rational creature.

2. Logically sound; not contradictory or otherwise absurd.

   His statements were quite rational.

3. (of a person or personal characteristics) Healthy or balanced intellectually; exhibiting reasonableness.

   rational conduct

4. (mathematics, arithmetic, number theory, not comparable) Of a number, capable of being expressed as the ratio of two integers.

   $\tfrac{3}{4}$ is a rational number, but √2 is an irrational number.

5. (mathematics, arithmetic, not comparable) Of an algebraic expression, capable of being expressed as the ratio of two polynomials.

Antonyms

• (reasonable): absurd, irrational, nonsensical
• (capable of reasoning): arational, irrational, non-rational
• (number theory): irrational

Related terms

Terms etymologically related to rational

arational irrational non-rational

rationale rationality rationalness

subrational suprarational

Translations

capable of reasoning

• Armenian: բանական (hy) (banakan)
• Catalan: racional (ca)
• Chinese:

  Mandarin: 合理的 (cmn) (hélǐ de), 理性的 (cmn) (lǐxìng de)

• Czech: racionální (cs)
• Finnish: rationaalinen (fi)
• French: rationnel (fr) m, rationnelle (fr) f
• German: vernünftig (de), sinnvoll (de), rational (de)
• Hungarian: értelmes (hu)

• Macedonian: рационален (mk) (racionálen) m, разумен (mk) (rázumen) m
• Romanian: rațional (ro) m and n
• Russian: мыслящий (ru) (mýsljaščij), разумный (ru) (razúmnyj), рациональный (ru) (racionálʹnyj)
• Scottish Gaelic: ciallach (gd)
• Serbo-Croatian:

  Cyrillic: рационалан (sh), разуман (sh)

  Roman: racionalan (sh), razuman (sh)

reasonable; not absurd

• Arabic: عقلاني (ar) (ʿaqlāniyy)
• Armenian: ռացիոնալ (hy) (ṙac’ional), խելացի (hy) (xelac’i), նպատակահարմար (hy) (npatakaharmar)
• Catalan: racional (ca)
• Chinese:

  Mandarin: 合理的 (cmn) (hélǐ de)

• Czech: racionální (cs)
• Danish: rationel (da)
• Dutch: rationeel (nl), redelijk (nl), verstandelijk (nl)
• Finnish: järkevä (fi), järjellinen (fi), järkiperäinen (fi), järkeenkäypä (fi), rationaalinen (fi)
• French: raisonnable (fr)
• German: vernünftig (de)
• Hungarian: racionális (hu), ésszerű (hu)
• Italian: razionale (it)

• Japanese: 合理的 (ja) (ごうりてき, gōriteki)
• Korean: 합리적 (ko) (hamnijeok)
• Macedonian: рационален (mk) (racionálen) m, разумен (mk) (rázumen) m, целисходен (mk) (celíshoden) m
• Polish: racjonalny (pl)
• Portuguese: racional (pt)
• Romanian: rațional (ro) m and n
• Russian: рациональный (ru) (racionálʹnyj), разумный (ru) (razúmnyj), целесообразный (ru) (celesoobráznyj), рассудительный (ru) (rassudítelʹnyj)
• Scottish Gaelic: ciallach (gd)
• Serbo-Croatian:

  Cyrillic: рационалан (sh), разуман (sh), разборит (sh)

  Roman: racionalan (sh), razuman (sh), razborit (sh)

• Swedish: rationell (sv)
• Telugu: హేతుబద్దమైన (te) (heatubaddamaina)

arithmetic: of a number

• Armenian: ռացիոնալ (hy) (ṙac’ional)
• Catalan: racional (ca)
• Chinese:

  Mandarin: 有理 (cmn) (yǒulǐ)

• Czech: racionální (cs)
• Dutch: rationeel (nl), rationele (nl)
• Finnish: rationaali- (fi)
• French: rationnel (fr) m, rationnelle (fr) f
• German: rational (de)
• Hungarian: racionális (hu)
• Icelandic: ræður (is) m

• Italian: razionale (it)
• Japanese: 有理の (ja) (ゆうりの, yūri-no)
• Macedonian: рационален (mk) (racionálen) m
• Polish: wymierny (pl) m
• Portuguese: racional (pt)
• Romanian: rațional (ro) n
• Russian: рациональный (ru) (racionálʹnyj)
• Serbo-Croatian:

  Cyrillic: рационалан (sh)

  Roman: racionalan (sh)

• Swedish: rationell (sv)

arithmetic: of an algebraic expression

• Armenian: ռացիոնալ (hy) (ṙac’ional)
• Chinese:

  Mandarin: 有理 (cmn) (yǒulǐ)

• Finnish: rationaali- (fi)
• German: rational (de)
• Icelandic: ræður (is) m

• Japanese: 有理の (ja) (ゆうりの, yūri-no)
• Macedonian: рационален (mk) (racionálen) m
• Russian: рациональный (ru) (racionálʹnyj)
• Serbo-Croatian:

  Cyrillic: рационалан (sh)

  Roman: racionalan (sh)

Etymology 2

From Old French rational, from Medieval Latin rationale (“a pontifical stole, a pallium, an ornament worn over the chasuble”), neuter of Latin rationalis (“rational”), for which see the first etymology.

Noun

rational (plural rationals)

1. (mathematics) A rational number: a number that can be expressed as the quotient of two integers.

   The quotient of two rationals is again a rational.

2. A rational being.

   (Can we find and add a quotation of Young to this entry?)

Translations

rational number — see rational number

References

• rational in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913
• rational in The Century Dictionary, The Century Co., New York, 1911

Anagrams

• notarial