from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Equal, as in value, force, or meaning.
  • adj. Having similar or identical effects.
  • adj. Being essentially equal, all things considered: a wish that was equivalent to a command.
  • adj. Mathematics Capable of being put into a one-to-one relationship. Used of two sets.
  • adj. Mathematics Having virtually identical or corresponding parts.
  • adj. Mathematics Of or relating to corresponding elements under an equivalence relation.
  • adj. Chemistry Having the same ability to combine.
  • adj. Logic Having equivalence: equivalent propositions.
  • n. Something that is essentially equal to another: "Prejudicing vital foreign policy considerations in order to rescue individuals finds its domestic equivalent in the inflated awards paid to ... accident and malpractice victims” ( Moorhead Kennedy).
  • n. Chemistry Equivalent weight.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Similar or identical in value, meaning or effect; virtually equal.
  • adj. Of two sets, having a one-to-one relationship.
  • adj. Relating to the corresponding elements of an equivalence relation.
  • adj. Having the equal ability to combine.
  • adj. Of a map, equal-area.
  • n. Anything that is virtually equal to another.
  • n. An equivalent weight.
  • v. To make equivalent to; to equal.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Equal in worth or value, force, power, effect, import, and the like; alike in significance and value; of the same import or meaning.
  • adj. Equal in measure but not admitting of superposition; -- applied to magnitudes.
  • adj. Contemporaneous in origin.
  • n. Something equivalent; that which is equal in value, worth, weight, or force.
  • n. That comparative quantity by weight of an element which possesses the same chemical value as other elements, as determined by actual experiment and reference to the same standard. Specifically: (a) The comparative proportions by which one element replaces another in any particular compound; thus, as zinc replaces hydrogen in hydrochloric acid, their equivalents are 32.5 and 1. (b) The combining proportion by weight of a substance, or the number expressing this proportion, in any particular compound.
  • n. A combining unit, whether an atom, a radical, or a molecule.
  • transitive v. To make the equivalent to; to equal; equivalence.

from The Century Dictionary and Cyclopedia

  • Equal in value, force, measure, power, effect, import, or meaning; correspondent; agreeing; tantamount: as, circumstantial evidence may be almost equivalent to full proof.
  • In geology, contemporaneous in origin; corresponding in position in the scale of rocks: as, the equivalent strata of different countries. See II., 2.
  • In geometry, having equal areas or equal dimensions: said of surfaces or magnitudes.
  • In biology, having the same morphic valence; homologous in structure.
  • n. That which is equal in value, measure, power, force, import, or meaning, to something else; something that corresponds, balances, compensates, etc.
  • n. In geology, a stratum or series of strata in one district formed contemporaneously with a stratum or series of a different lithological character in a different region, or occupying the same relative position in the scale of rocks, and agreeing in the character of its fossils if deposited under similar circumstances: thus, the Caen building-stone of France is the equivalent of the English Bath oölite.
  • To produce or constitute an equivalent to; answer in full proportion; equal or equalize.
  • In geometry: Said of two polygons if they can be cut into a finite number of triangles congruent in pairs.
  • In chem., applied to the respective quantities of different substances which are capable of replacing each other in combination with a fixed quantity of some particular substance. These mutually replaceable quantities of such substances are said to be equivalent to each other. See equiralence. 2.
  • n. See equivalence, 2.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. the atomic weight of an element that has the same combining capacity as a given weight of another element; the standard is 8 for oxygen
  • adj. being essentially equal to something
  • n. a person or thing equal to another in value or measure or force or effect or significance etc


Middle English, from Late Latin aequivalēns, aequivalent-, present participle of aequivalēre, to have equal force : Latin aequi-, equi- + Latin valēre, to be strong.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin aequivalentem, accusative singular of aequivalēns, present active participle of aequivaleō ("I am equivalent, have equal power"). (Wiktionary)


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