[ih-kwiv-uh-luh nt or for 5, ee-kwuh-vey-luh nt]
  1. equal in value, measure, force, effect, significance, etc.: His silence is equivalent to an admission of guilt.
  2. corresponding in position, function, etc.: In some ways their prime minister is equivalent to our president.
  3. Geometry. having the same extent, as a triangle and a square of equal area.
  4. Mathematics. (of two sets) able to be placed in one-to-one correspondence.
  5. Chemistry. having the same capacity to combine or react chemically.
  1. something that is equivalent.

Origin of equivalent

1425–75; late Middle English < Late Latin aequivalent- (stem of aequivalēns), present participle of aequivalēre. See equi-, -valent
Related formse·quiv·a·lent·ly, adverbnon·e·quiv·a·lent, adjective, nounnon·e·quiv·a·lent·ly, adverbqua·si-e·quiv·a·lent, adjectivequa·si-e·quiv·a·lent·ly, adverbsu·per·e·quiv·a·lent, adjective, nounun·e·quiv·a·lent, adjectiveun·e·quiv·a·lent·ly, adverb
Can be confusedequivalent equivocal

Synonyms for equivalent

1. See equal.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for quasi-equivalent


  1. equal or interchangeable in value, quantity, significance, etc
  2. having the same or a similar effect or meaning
  3. maths
    1. having a particular property in common; equal
    2. (of two equations or inequalities) having the same set of solutions
    3. (of two sets) having the same cardinal number
  4. maths logic (of two propositions) having an equivalence between them
  1. something that is equivalent
  2. short for equivalent weight
Derived Formsequivalently, adverb

Word Origin for equivalent

C15: from Late Latin aequivalēns, from aequivalēre to be equally significant, from Latin aequi- equi- + valēre to be worth
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 quasi-equivalent



early 15c., from Middle French equivalent and directly from Late Latin aequivalentem (nominative aequivalens) "equivalent," present participle of aequivalere "be equivalent," from Latin aequus "equal" (see equal) + valere "be well, be worth" (see valiant). As a noun from c.1500.

Online Etymology Dictionary, © 2010 Douglas Harper

quasi-equivalent in Medicine


  1. Equal, as in value, force, or meaning.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

quasi-equivalent in Science


  1. Equal, as in value, meaning, or force.
    1. Of or relating to a relation between two elements that is reflexive, symmetric, and transitive.
    2. Having a one-to-one correspondence, as between parts. Two triangles having the same area are equivalent, as are two congruent geometric figures.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.