Definition of rational in English:

rational

Syllabification: ra·tion·al
Pronunciation: /ˈraSHənl, ˈraSHnəl
 
/

adjective

  • 1Based on or in accordance with reason or logic: I’m sure there’s a perfectly rational explanation
    More example sentences
    • Hegel develops his rational ontology of gender within a logic of oppositions.
    • But for many people, their faith isn't based around an irrational fervour, and it isn't based around rational logic.
    • The ideals of liberty, equality, and fraternity proved inadequate as bases for a fully rational society.
    Synonyms
    logical, reasoned, sensible, reasonable, cogent, intelligent, judicious, shrewd, common-sense, commonsensical, sound, prudent; down-to-earth, practical, pragmatic
  • 1.1(Of a person) able to think clearly, sensibly, and logically: Andrea’s upset—she’s not being very rational
    More example sentences
    • Unlike the first two, Proviesque rarely displays a logical structure that can be followed by sensible rational people.
    • To be honest, I once thought about having another woman, but I did not do it because I was able to be rational, I did not want to take any risks.
    • I have a friend, a sensible, rational creature, not outwardly generous, but happy to share a garibaldi if pressed.
    Synonyms
    sane, compos mentis, in one's right mind, of sound mind; normal, balanced, grounded, lucid, coherent
    informal all there
  • 1.2Endowed with the capacity to reason: man is a rational being
    More example sentences
    • Kant said that the mind is rational, it is endowed with Reason.
    • Since men are rational and egoistic, endowed with the right of property, the composition of output should be determined by consumer sovereignty.
    • There is implanted in every rational being the capacity to distinguish the true from the false, to weigh the evidence, and to confront the world without illusions.
    Synonyms
    intelligent, thinking, reasoning; cerebral, logical, analytical
    formal ratiocinative
  • 2 Mathematics (Of a number, quantity, or expression) expressible, or containing quantities that are expressible, as a ratio of whole numbers. When expressed as a decimal, a rational number has a finite or recurring expansion.
    More example sentences
    • The set of rational numbers is denumerable, that is, it has cardinal number d.
    • His idea was that every real number r divides the rational numbers into two subsets, namely those greater than r and those less than r.
    • Term formalism can perhaps be extended to the integers and rational numbers, but what are the real numbers supposed to be?

noun

Mathematics Back to top  
  • A rational number.
    More example sentences
    • The construction of the reals from the integers proceeds in several stages: first axiomatize the positive integers, then construct negative from positive integers, then rationals from integers, and finally reals from rationals.
    • Thus a set that includes the rationals has been put into a systematic one-to-one correspondence with the natural numbers.
    • She then extended the function to the negative rationals.

Derivatives

rationality

Pronunciation: /ˌraSHəˈnalətē/
noun
More example sentences
  • Truth, science, intellectual inquiry and rationality are inextricably bound together.
  • His threat lay in his cold rationality and his overwhelming intellectual authority.
  • Our judgements are constrained by rationality to the extent that we cannot just label any movement a cult by pure whim.

rationally

Pronunciation: /ˈraSHənl-ē, ˈraSHnəlē/
adverb
More example sentences
  • From this perspective you will be able to think much more clearly and rationally.
  • Her philosophy was that everything could be explained logically and rationally.
  • Anger clearly breeds stupidity, but let us try to think rationally this Sunday.

Origin

late Middle English (in the sense 'having the ability to reason'): from Latin rationalis, from ratio(n-) 'reckoning, reason' (see ratio).

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