Dictionary > English Dictionary > Definition, synonym and antonym of rational
Meaning of rational by Wiktionary Dictionary


    Alternative forms


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

    Etymology 1

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


    rational ( comparative more rational, superlative most rational )

    1. Capable of reasoning.
      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 .
    Related terms

    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 .


    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? )

    See also

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


Explanation of rational by Wordnet Dictionary


    1. having its source in or being guided by the intellect ( as distinguished from experience or emotion )

    2. a rational analysis
    3. of or associated with or requiring the use of the mind

    4. the triumph of the rational over the animal side of man
    5. consistent with or based on or using reason

    6. rational behavior
      a process of rational inference
      rational thought
    7. capable of being expressed as a quotient of integers

    8. rational numbers
    1. an integer or a fraction