noun

- the act of equating or making equal; equalization: the symbolic equation of darkness with death.
- equally balanced state; equilibrium.
- Mathematics. an expression or a proposition, often algebraic, asserting the equality of two quantities.
- Also called chemical equation. Chemistry. a symbolic representation showing the kind and amount of the starting materials and products of a reaction.

noun

- a mathematical statement that two expressions are equal: it is either an identity in which the variables can assume any value, or a conditional equation in which the variables have only certain values (roots)
- the act of regarding as equal; equating
- the act of making equal or balanced; equalization
- a situation, esp one regarded as having a number of conflicting elementswhat you want doesn’t come into the equation
- the state of being equal, equivalent, or equally balanced
- a situation or problem in which a number of factors need to be considered
- See chemical equation
- astronomy See personal equation

late 14c., a term in astrology; meaning “action of making equal” is from 1650s; mathematical sense is from 1560s, on notion of equalizing the expressions; from Latin aequationem (nominative aequatio) “an equal distribution, community,” from past participle stem of aequare (see equal (adj.)). Chemistry sense is from 1807.

n.

- A statement asserting the equality of two mathematical expressions, usually written as a linear array of symbols that are separated into left and right sides and are joined by an equal sign.
- 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, arrow, or set of opposing arrows.

- Mathematics A written statement indicating the equality of two expressions. It consists of a sequence of symbols that is split into left and right sides joined by an equal sign. For example, 2 + 3 + 5 = 10 is an equation.
- Chemistry A written representation of a chemical reaction, in which the symbols and amounts of the reactants are separated from those of the products by an equal sign, arrow, or a set of opposing arrows. For example, Ca(OH)2 + H2SO4 = CaSO4 + 2H2O, is an equation.

An expression of equality between two formulas in mathematics. The two formulas are written with an equal sign between them: 2 + 2 = 4 is an equation, as is E = mc2.