rational

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See also: rațional

English

Alternative forms

Pronunciation

Etymology 1

From Old French rationel, rational, from Latin rationalis (of or belonging to reason, rational, reasonable; having a ratio), from ratio (reason; calculation).

Adjective

rational (comparative more rational, superlative most rational)

  1. Capable of reasoning.
    Man is a rational creature.
    • 2001, Mark Sainsbury, chapter 1, in Logical Forms — An Introduction to Philosophical Logic, 2nd edition, Blackwell Publishing, →ISBN, §7, page 32:
      The utility of valid arguments is a monument to our frailty: to the fact that we are not completely rational beings.
  2. Logically sound; not self-contradictory or otherwise absurd.
    His statements were quite rational.
  3. (of a person or personal characteristics) Healthy or balanced intellectually; exhibiting reasonableness.
    rational conduct
    • 1867 C. Handfield Jones, Case Of Low Fever: Delirium: Incomplete Dementia. The British Medical Journal Vol. 2, No. 344, Aug. 3
      Temperature 99.8 degrees. Pulse 104. She was quite conscious and rational at times, at others very noisy.
    • 2014 June 21, “Magician’s brain”, in The Economist, volume 411, number 8892:
      The Newton that emerges from the manuscripts is far from the popular image of a rational practitioner of cold and pure reason. The architect of modern science was himself not very modern. He was obsessed with alchemy.
  4. (mathematics, not comparable) Comprising, or expressible as, a ratio
    1. (arithmetic) Of a number, capable of being expressed as the ratio of two integers.
      ¾ is a rational number, but √2 is an irrational number.
    2. (algebra) Of an algebraic expression in indeterminates, or more generally a function: capable of being expressed as the ratio of two polynomials.
    3. (algebraic geometry) Of a variety: (informally) geometrically simple almost everywhere; (formally) birationally equivalent to projective space
    4. (algebraic geometry) Of a function between varieties: acting as a morphism on an open subset of its domain.
    5. (algebraic geometry) Of a point on an algebraic variety over a field: whose coordinates belong to the field in question (in contrast to those points of the variety which are only defined over the algebraic closure of the base field).
  5. (chemistry) Expressing the type, structure, relations, and reactions of a compound; graphic; said of formulae.
  6. (physics) Expressing a physical object.
    A rational table is physical, a written table is neither.
Antonyms
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Translations

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.
Translations

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. Translation of λογεῖον (logeîon) or perhaps λόγιον (lógion, oracle) in the Septuagint version of Exodus 28.

Noun

rational (plural rationals)

  1. (historical) The breastplate worn by Israelite high priests.
Translations

References

Further reading

  • "rational" in Raymond Williams, Keywords (revised), 1983, Fontana Press, page 252.

Anagrams

French

Pronunciation

Noun

rational f (plural rationaux)

  1. rationale (religious clothing)

Further reading

German

Etymology

Borrowed from Latin rationalis.

Pronunciation

  • IPA(key):
  • Hyphenation: ra‧ti‧o‧nal
  • Audio:(file)

Adjective

rational (strong nominative masculine singular rationaler, comparative rationaler, superlative am rationalsten)

  1. rational

Declension

Further reading

  • rational” in Duden online
  • rational” in Digitales Wörterbuch der deutschen Sprache