[rash-uh-nl, rash-nl]



Mathematics. rational number.

Origin of rational

1350–1400; Middle English racional < Latin ratiōnālis, equivalent to ratiōn- (stem of ratiō) reason + -ālis -al1
Related formsra·tion·al·ly, adverbra·tion·al·ness, nounan·ti·ra·tion·al, adjectivean·ti·ra·tion·al·ly, adverbhy·per·ra·tion·al, adjectivehy·per·ra·tion·al·ly, adverbnon·ra·tion·al, adjectivenon·ra·tion·al·ly, adverbo·ver·ra·tion·al, adjectiveo·ver·ra·tion·al·ly, adverbpre·ra·tion·al, adjectivequa·si-ra·tion·al, adjectivequa·si-ra·tion·al·ly, adverbtrans·ra·tion·al, adjectivetrans·ra·tion·al·ly, adverbul·tra·ra·tion·al, adjectiveul·tra·ra·tion·al·ly, adverbun·ra·tion·al, adjectiveun·ra·tion·al·ly, adverb
Can be confusedrational reasonable (see synonym study at reasonable)

Synonyms for rational

2. intelligent, wise, judicious, sagacious, enlightened. 6. See reasonable.

Antonyms for rational

2. stupid. 3. insane.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for hyper-rational

Historical Examples of hyper-rational

  • Slowly, slowly, unnaturally—as though energized by some hyper-rational power—his lips and tongue moved.

    There is a Reaper ...

    Charles V. De Vet

British Dictionary definitions for hyper-rational



using reason or logic in thinking out a problem
in accordance with the principles of logic or reason; reasonable
of sound mind; sanethe patient seemed quite rational
endowed with the capacity to reason; capable of logical thoughtman is a rational being
maths expressible as a ratio of two integers or polynomialsa rational number; a rational function


maths a rational number
Derived Formsrationally, adverbrationalness, noun

Word Origin for rational

C14: from Latin ratiōnālis, from ratiō reason
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for hyper-rational



late 14c., "pertaining to reason;" mid-15c., "endowed with reason," from Old French racionel and directly from Latin rationalis "of or belonging to reason, reasonable," from ratio (genitive rationis) "reckoning, calculation, reason" (see ratio).

Online Etymology Dictionary, © 2010 Douglas Harper

hyper-rational in Medicine




Having or exercising the ability to reason.
Influenced by reasoning rather than by emotion.
Of sound mind; sane.
Based on scientific knowledge or theory rather than practical observation.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.