The Meaning of Rational: What It Is and How To Use It

Do you know the definition of rational? This article will provide you with all of the information you need on the word rational, including its definition, etymology, usage, example sentences, and more!

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What does the word rational mean?

According to Collins English Dictionary and the American Heritage Unabridged Dictionary of the English Language, the word rational is an adjective that can refer to someone who bases their decisions on reason rather than emotion. Rational beings and rational creatures have a sound mind and rational thoughts. This person is in full possession of their good judgment. Other things besides people can be rational, like rational creatures, a rational plan, a rational negotiator, a rational faculty, a rational plan, rational analysis, and more. These things all have common sense, or can solve intellectual problems through the process of rational inference. They make use of the mind and intellect to apply principles of logic and sound judgment to situations. Rational is three syllables – ra-tion-al, and the pronunciation of rational is ræʃənəl.

Rational is also a term in mathematics which refers to a real number of quantities expressible as the ratio of two integers where the second integer is not equal to zero. All integers, polynomials, and fractions are rational numbers.  

Different languages around the world use words that mean rational. In looking at this list of translations of rational from Word Sense, you may notice that a lot of these look and sound similar to the word rational. These are called cognates, which are often formed when two words have the same root or language of origin. 

  •  French: raisonnable‎
  •  Roman: racionalan‎, razuman‎, razborit‎
  •  Polish: racjonalny‎
  •  Arabic: عَقْلَانِيّ‎
  •  Cyrillic: рационалан‎, разуман‎, разборит‎
  •  Hungarian: racionális‎, észszerű‎
  •  Russian: рациона́льный‎, разу́мный‎, целесообра́зный‎, рассуди́тельный‎
  •  Romanian: rațional‎ (masc.) (n)
  •  Macedonian: рационален‎, разумен‎, целисходен‎
  •  Telugu: హేతుబద్దమైన‎ (heatubaddamaina)
  •  Japanese: 合理的‎ (ごうりてき, gōriteki)
  •  Korean: 합리적‎
  •  Catalan: racional‎
  •  Czech: racionální‎
  •  Mandarin: 合理‎
  •  Finnish: järkevä‎, järjellinen‎, järkiperäinen‎, järkeenkäypä‎, rationaalinen‎
  •  Danish: rationel‎
  •  German: vernünftig‎
  •  Spanish: razonable‎
  •  Swedish: rationell‎
  •  Dutch: rationeel‎, redelijk‎, verstandelijk‎
  •  Scottish Gaelic: ciallach‎
  •  Armenian: ռացիոնալ‎, խելացի‎, նպատակահարմար‎
  •  Maltese: għaqli‎
  •  Portuguese: racional‎
  •  Italian: razionale‎

What is the origin of the word rational?

According to Etymonline, the word rational has been used since the late c14 as the Middle English racional. This word has been used since mid-c15 to describe people. This word comes from the Old French racional, Old French rationel and Old French racionel meaning pontifical stole, a pallium, an ornament, the neuter of Latin rationalis/Latin ratiōnālis, from the Latin ratio/ratiō, the genitive rationis meaning a reckoning or reason. These are also seen in the first etymology of the Medieval Latin rationale. This has been used in the field of mathematics since the 1560s. One can add the suffixes ly, ity, ise, e, ist, and the prefix ir to form the related words irrational (adj.), ratio (n.), ration (n.), rationale (n.), rationalist (n.), rationality (n.), rationally (adv.) and rationalize (v.).

What are synonyms and antonyms of rational?

There are a number of different words that a person can choose to use in place of the word rational. These are called synonyms, which are words and phrases that have the same meaning or definition as another given word or phrase. Learning synonyms is a great way to easily expand your English language vocabulary and help you avoid repeating yourself when writing or speaking. The below list of synonyms for the word rational is provided by Thesaurus

  •  knowing
  •  sober
  •  prudent
  •  thoughtful
  •  lucid
  •  sane
  •  objective
  •  well-advised
  •  wise
  •  logical
  •  balanced
  •  sensible
  •  discerning
  •  reasonable
  •  intelligent
  •  normal
  •  thinking
  •  all there
  •  reasoning
  •  cerebral
  •  circumspect
  •  discriminating
  •  stable
  •  analytical
  •  deductive
  •  perspicacious
  •  cool
  •  calm
  •  impartial
  •  together
  •  sound
  •  sagacious
  •  deliberate
  •  enlightened
  •  cognitive
  •  intellectual
  •  collected
  •  philosophic
  •  of sound mind
  •  reflective
  •  levelheaded
  •  far-sighted
  •  ratiocinative
  •  synthetic
  •  realistic
  •  judicious

There are also plenty of different words that have the opposite meaning of the word rational. These opposite words are called antonyms, which are another great, quick and easy way to expand your English language vocabulary. This list of antonyms is also provided by Thesaurus.

  •  fallacious
  •  senseless
  •  reasonless
  •  silly
  •  preposterous
  •  insane
  •  aberrant
  •  demented
  •  off-the-wall
  •  loony
  •  delirious
  •  nutty
  •  incoherent
  •  unthinking
  •  wild
  •  cockamamie
  •  ridiculous
  •  kooky
  •  disconnected
  •  illogical
  •  sophistic
  •  stupid
  •  injudicious
  •  unsound
  •  foolish
  •  unreasoning
  •  absurd
  •  wacky
  •  crazy
  •  brainless
  •  unreasonable
  •  unwise
  •  mindless
  •  unstable
  •  mad
  •  invalid
  •  flaky
  •  freaky
  •  irrational
  •  nonsensical
  •  disjointed
  •  distraught
  •  specious
  •  wrong
  •  raving

How can the word rational be used in a sentence?

The word rational can be used in many different sentences in the English language. Using words in a sentence is a great way to memorize their definitions. You can also try making flashcards or quizzes to test your knowledge of the definitions of many different words. Try using this word of the day in a sentence today. You never know, it might become one of your new favorites. Below are a couple of examples of the word rational to get you started.

Mora is an extremely rational person. She works in economic development with various formulae every day and utility to predict economics. 

The student studied evolutionary biology because she thought it was a rational choice to direct her toward medical school, but she is much more interested in psychology, sociology, and political science. She wished she had not gone along with conformity and thought outside the box. 

When they were studying rational numbers and the quotient of integers in math class, the student became very confused. Why would they study imaginary numbers if they did not exist? He only understood math when it was wholly concrete.

Overall, the word rational means thinking with a sound mind or logic rather than emotions or feelings. This is also  a term in mathematics that refers to integers and fractions that are not divided by zero. 


  1. RATIONAL Synonyms: 66 Synonyms & Antonyms for RATIONAL | Thesaurus 
  2. IRRATIONAL Synonyms: 58 Synonyms & Antonyms for IRRATIONAL | Thesaurus 
  3. rational: meaning, origin, translation | Word Sense 
  4. rational | Origin and meaning of rational | Online Etymology Dictionary 
  5. Rational definition and meaning | Collins English Dictionary