[pruh-pawr-shuh-nl, -pohr-]
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  1. having due proportion; corresponding.
  2. being in or characterized by proportion.
  3. of, relating to, or based on proportion; relative.
  4. Mathematics.
    1. (of two quantities) having the same or a constant ratio or relation: The quantities y and x are proportional if y/x = k, where k is the constant of proportionality.
    2. (of a first quantity with respect to a second quantity) a constant multiple of: The quantity y is proportional to x if y = kx, where k is the constant of proportionality.

Origin of proportional

1350–1400; Middle English proporcional < Latin prōportiōnālis. See proportion, -al1
Related formspro·por·tion·al·i·ty, nounpro·por·tion·al·ly, adverbin·ter·pro·por·tion·al, adjectivenon·pro·por·tion·al, adjectivenon·pro·por·tion·al·ly, adverbsub·pro·por·tion·al, adjectivesub·pro·por·tion·al·ly, adverbun·pro·por·tion·al, adjectiveun·pro·por·tion·al·ly, adverb
Can be confusedproportional proportionate

Synonyms for proportional

See more synonyms for on Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for proportionality

Contemporary Examples of proportionality

Historical Examples of proportionality

British Dictionary definitions for proportionality


  1. of, involving, or being in proportion
  2. maths having or related by a constant ratio
  1. maths an unknown term in a proportionin a/b = c/x, x is the fourth proportional
Derived Formsproportionality, nounproportionally, 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 proportionality

1560s, from French proportionalité (14c.) or directly from Medieval Latin proportionalitas, from proportio (see proportion).



late 14c. (implied in proportionally), from Late Latin proportionalis "pertaining to proportions," from proportio (see proportion). Related: Proportionally.

Online Etymology Dictionary, © 2010 Douglas Harper