equivalent

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Equal, as in value, force, or meaning.
2. adj. Having similar or identical effects.
3. adj. Being essentially equal, all things considered: a wish that was equivalent to a command.
4. adj. Mathematics Capable of being put into a one-to-one relationship. Used of two sets.
5. adj. Mathematics Having virtually identical or corresponding parts.
6. adj. Mathematics Of or relating to corresponding elements under an equivalence relation.
7. adj. Chemistry Having the same ability to combine.
8. adj. Logic Having equivalence: equivalent propositions.
9. 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).
10. n. Chemistry Equivalent weight.

Century Dictionary and Cyclopedia

1. Equal in value, force, measure, power, effect, import, or meaning; correspondent; agreeing; tantamount: as, circumstantial evidence may be almost equivalent to full proof.
2. In geology, contemporaneous in origin; corresponding in position in the scale of rocks: as, the equivalent strata of different countries. See II., 2.
3. In geometry, having equal areas or equal dimensions: said of surfaces or magnitudes.
4. In biology, having the same morphic valence; homologous in structure.
5. n. That which is equal in value, measure, power, force, import, or meaning, to something else; something that corresponds, balances, compensates, etc.
6. 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.
7. To produce or constitute an equivalent to; answer in full proportion; equal or equalize.
8. In geometry: Said of two polygons if they can be cut into a finite number of triangles congruent in pairs.
9. 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.
10. n. See equivalence, 2.

Wiktionary

1. adj. similar or identical in value, meaning or effect; virtually equal
2. adj. of two sets, having a one-to-one relationship
3. adj. relating to the corresponding elements of an equivalence relation
4. adj. having the equal ability to combine
5. adj. of a map, equal-area
6. n. anything that is virtually equal to another
7. n. an equivalent weight

GNU Webster's 1913

1. adj. Equal in worth or value, force, power, effect, import, and the like; alike in significance and value; of the same import or meaning.
2. adj. Equal in measure but not admitting of superposition; -- applied to magnitudes.
3. adj. Contemporaneous in origin.
4. n. Something equivalent; that which is equal in value, worth, weight, or force.
5. 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.
6. n. A combining unit, whether an atom, a radical, or a molecule.
7. v. To make the equivalent to; to equal; equivalence.

WordNet 3.0

1. 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
2. adj. being essentially equal to something
3. n. a person or thing equal to another in value or measure or force or effect or significance etc