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

  • n. The act or process of equating or of being equated.
  • n. The state of being equal.
  • n. Mathematics A statement asserting the equality of two expressions, usually written as a linear array of symbols that are separated into left and right sides and joined by an equal sign.
  • n. Chemistry A representation of a chemical reaction, usually written as a linear array in which the symbols and quantities of the reactants are separated from those of the products by an equal sign, an arrow, or a set of opposing arrows.
  • n. A complex of variable elements or factors: "The world was full of equations . . . there must be an answer for everything, if only you knew how to set forth the questions” ( Anne Tyler).

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. An assertion that two expressions are equal, expressed by writing the two expressions separated by an equal sign; from which one is to determine a particular quantity.
  • n. A small correction to observed values to remove the effects of systematic errors in an observation.

from the GNU version of the Collaborative International Dictionary of English

  • n. A making equal; equal division; equality; equilibrium.
  • n. An expression of the condition of equality between two algebraic quantities or sets of quantities, the sign = being placed between them
  • n. A quantity to be applied in computing the mean place or other element of a celestial body; that is, any one of the several quantities to be added to, or taken from, its position as calculated on the hypothesis of a mean uniform motion, in order to find its true position as resulting from its actual and unequal motion.

from The Century Dictionary and Cyclopedia

  • n. A making equal, or an equal division; equality.
  • n. In mathematics, a proposition asserting the equality of two quantities, and expressed by the sign = between them; or an expression of the same quantity in two terms dissimilar but of equal value: as, 3 lb. = 48 oz.; x = b + m − r.
  • n. In astronomy, the correction or quantity to be added to or subtracted from the mean position of a heavenly body to obtain the true position; also, in a more general sense, the correction arising from any erroneous supposition whatever.
  • n. In chem., a collection of symbols used to indicate that two or more definite bodies, simple or compound, having been brought within the sphere of chemical action, a reaction will take place, and new bodies be produced.
  • n. An equation for the steady motion of a liquid, namely, where p is the pressure, ρ the density, V the potential of the impressed forces, q the velocity, and C a constant for each stream-line and vortex-line, and in the case of irrotational motion a constant for all space.
  • n. with modern writers, a solution which is a particular case of the general solution;
  • n. with older writers, any solution not general. A singular solution is one which is neither general nor implied in the general solution. The complete integral of a partial differential equation is a solution containing the full number of arbitrary constants or functions.
  • n. In modern writings, the correction to be applied to the position of a planet or to the time of an eclipse, etc., owing to the finite velocity of light.
  • n. In modern astron., the excess of the true over the mean anomaly. (Gauss, Theoria Motus, I. 7.)
  • n. The equation of the argument. (Kepler, De Motibus Martis, I. iv.)
  • n. Any one of the usual equations of hydrodynamics, where the components of the velocity at fixed points of space are taken as variables: so called in contradistinction to the Lagrangian equations where the coordinates of a definite particle are taken as variables; these equations, though also discovered by Euler, having been used by Lagrauge.
  • n. A general equation of hydrodynamics, in which, instead of considering the velocity at each fixed point of space, the motion of each particle is followed out. This is called a Lagrangian equation because used by Lagrange in his “Méchanique Analitique,” though invented by Euler.
  • n. An equation of analytical geometry in which certain curves are represented by single letters. Thus, if U = 0, V = 0, W = 0, represent the equations of three circles, UV = W is the symbolic equation of a bicircular quartic
  • n.
  • n. In the calculus, an equation which contains no differentials.

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

  • n. the act of regarding as equal
  • n. a state of being essentially equal or equivalent; equally balanced
  • n. a mathematical statement that two expressions are equal


from Wiktionary, Creative Commons Attribution/Share-Alike License

From Latin aequātiō ("an equalizing").



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