• synonyms


[in-kuh-men-ser-uh-buh l, -sher-]
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  1. not commensurable; having no common basis, measure, or standard of comparison.
  2. utterly disproportionate.
  3. Mathematics. (of two or more quantities) having no common measure.
  1. something that is incommensurable.
  2. Mathematics. one of two or more incommensurable quantities.

Origin of incommensurable

From the Late Latin word incommēnsūrābilis, dating back to 1550–60. See in-3, commensurable
Related formsin·com·men·su·ra·bil·i·ty, in·com·men·su·ra·ble·ness, nounin·com·men·su·ra·bly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for incommensurability

Historical Examples

  • This is the fifth example of irrationality and incommensurability.

    The Way To Geometry

    Peter Ramus

  • This is the fourth example of irrationality, or incommensurability.

British Dictionary definitions for incommensurability


  1. incapable of being judged, measured, or considered comparatively
  2. (postpositive foll by with) not in accordance; incommensurate
  3. maths
    1. (of two numbers) having an irrational ratio
    2. not having units of the same dimension
    3. unrelated to another measurement by integral multiples
  1. something incommensurable
Derived Formsincommensurability or incommensurableness, nounincommensurably, adverb
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 incommensurability


1560s; see incommensurable + -ity.



1550s, from Middle French incommensurable or directly from Medieval Latin incommensurabilis, from in- "not, opposite of, without" (see in- (1)) + Late Latin commensurabilis, from Latin com- "with" + mensurabilis "measurable," from mensurare "to measure" (see measure (v.)). Related: Incommensurably.

Online Etymology Dictionary, © 2010 Douglas Harper