from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Equal, as in value, force, or meaning.
  • adjective Having similar or identical effects.
  • adjective Being essentially equal, all things considered.
  • adjective Capable of being put into a one-to-one relationship. Used of two sets.
  • adjective Having virtually identical or corresponding parts.
  • adjective Of or relating to corresponding elements under an equivalence relation.
  • adjective Chemistry Having the same ability to combine.
  • adjective Logic Having equivalence.
  • noun Something that is essentially equal to another.
  • noun Chemistry Equivalent weight.

from The Century Dictionary.

  • 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.
  • noun See equivalence, 2.
  • To produce or constitute an equivalent to; answer in full proportion; equal or equalize.
  • 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.
  • noun That which is equal in value, measure, power, force, import, or meaning, to something else; something that corresponds, balances, compensates, etc.
  • noun 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.

from the GNU version of the Collaborative International Dictionary of English.

  • adjective Equal in worth or value, force, power, effect, import, and the like; alike in significance and value; of the same import or meaning.
  • adjective (Geom.) Equal in measure but not admitting of superposition; -- applied to magnitudes.
  • adjective (Geol.) Contemporaneous in origin.
  • transitive verb rare To make the equivalent to; to equal; equivalence.
  • noun Something equivalent; that which is equal in value, worth, weight, or force.
  • noun (Chem.) 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.
  • noun (Chem.) A combining unit, whether an atom, a radical, or a molecule.
  • noun (Physics) originally defined as the number of units of work which the unit of heat can perform, equivalent to the mechanical energy which must be expended to raise the temperature of a pound of water one degree Fahrenheit; later this value was defined as one British thermal unit (B.t.u). Its value was found by Joule to be 772 foot pounds; later measurements give the value as 777.65 foot-pounds, equivalent to 107.5 kg-meters. This value was originally called Joule's equivalent, but the modern Joule is defined differently, being 107 ergs. The B.t.u. is now given as 1,054.35 absolute Joules, and therefore 1 calorie (the amount of heat needed to raise one gram of water one degree centigrade) is equivalent to 4.186 Joules.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

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

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

  • noun 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
  • adjective being essentially equal to something
  • noun a person or thing equal to another in value or measure or force or effect or significance etc


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

[Middle English, from Late Latin aequivalēns, aequivalent-, present participle of aequivalēre, to have equal force : Latin aequi-, equi- + Latin valēre, to be strong; see wal- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Latin aequivalentem, accusative singular of aequivalēns, present active participle of aequivaleō ("I am equivalent, have equal power").


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