rational rational /ˈræʃnəl/

adjective

1. () Consistent with or based on or using reason  ( rational )
   consistent with or based on or using reason
    Rational behavior
   rational behavior
    A process of rational inference
   a process of rational inference
    Rational thought
   rational thought
   
2. () Of or associated with or requiring the use of the mind  ( noetic , rational , intellectual )
   of or associated with or requiring the use of the mind
    Intellectual problems
   intellectual problems
    The triumph of the rational over the animal side of man
   the triumph of the rational over the animal side of man
   
3. Having its source in or being guided by the intellect (as distinguished from experience or emotion)  ( rational )
   having its source in or being guided by the intellect (as distinguished from experience or emotion)
    A rational analysis
   a rational analysis
   
4. (mathematics) capable of being expressed as a quotient of integers  ( rational )
   (mathematics) capable of being expressed as a quotient of integers
    Rational numbers
   rational numbers
   

noun

1. An integer or a fraction  ( rational , rational number )
   an integer or a fraction