equation

American  

[ih-kwey-zhuhn, -shuhn] / ɪˈkweɪ ʒən, -ʃən /

noun

• equations
  plural

1. the act of equating or making equal; equalization.

   the symbolic equation of darkness with death.

2. equally balanced state; equilibrium.

3. Mathematics. an expression or a proposition, often algebraic, asserting the equality of two quantities.

4. Also called chemical equation.  Chemistry. a symbolic representation showing the kind and amount of the starting materials and products of a reaction.

---

equation British  

/ ɪˈkweɪʒən, -ʃən /

noun

1. 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)

2. the act of regarding as equal; equating

3. the act of making equal or balanced; equalization

4. a situation, esp one regarded as having a number of conflicting elements

   what you want doesn't come into the equation

5. the state of being equal, equivalent, or equally balanced

6. a situation or problem in which a number of factors need to be considered

7. See chemical equation

8. astronomy See personal equation

---

equation Scientific  

/ ĭ-kwā′zhən /

1. 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.

2. 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 + H ₂ SO ₄ = CaSO ₄ + 2H ₂ O, is an equation.

---

Other Word Forms

Derived Forms

• nonequation
  noun
• equational
  adjective
• equationally
  adverb

Inflected Forms

Nouns

• equations
  plural

Etymology

Origin of equation

1350–1400; Middle English < Latin aequātiōn- (stem of aequātiō ) an equalizing. See equate, -ion

Explanation

In an equation, the quantities on both sides of the equal sign are equal. That's the mathematical meaning of equation, but equation can also be used in any number of situations, challenges, or efforts to solve a problem. The "equa" at the beginning of equation will be familiar from other words such as "equal," "equality," and "equate." All of these words have to do with making things balance out. An equation is a statement of the equality of two quantities. If that equation is not a mathematical one but rather, say, an interpersonal one, it's still a situation in which you might try to make the two sides equal. For example, taking marriage out of the equation might make it easier for two people to decide to stay together for a while.

Example Sentences

See Examples For:

equation equations

A freelancer by day, I’d appreciated teaching’s miraculous equation: I did my job, they paid me the first of every month.

From Salon ● Aug. 24, 2026

That leaves Moderna investors with a hard equation.

From The Wall Street Journal ● Aug. 23, 2026

The simplest way to get a general idea of whether you’ve saved enough for retirement is to start with one basic equation: Income minus spending equals what you need from your savings.

From MarketWatch ● Aug. 11, 2026

They log GPS coordinates, measure the distance to the road, and use a complicated equation to estimate the density of the animals in these woods and, from that, broader population health.

From BBC ● Aug. 8, 2026

It was the only way to be certain that there were no impurities in the equation, and no unknown factor that might affect the results.

From "Strange the Dreamer" by Laini Taylor

The universe may contain large amounts of invisible "dark matter" whose gravity supplies the additional pull, or "the fundamental equations for gravity need to be modified."

From Science Daily ● Aug. 25, 2026

If you imagine a collection of matter representing "a universe," Einstein's equations can tell you how that collection should evolve.

From Science Daily ● Aug. 18, 2026

One said he would keep working on partial differential equations, one said he wanted to experiment with artificial intelligence and one said she had absolutely no idea.

From The Wall Street Journal ● Aug. 1, 2026

Deng and his collaborators solved a problem within broader attempts to mathematically connect equations governing the motion of gases from the smallest to the largest scales, according to the university.

From The Wall Street Journal ● Jul. 24, 2026

Once again physicists are talking about the cosmological constant—the mysterious term that Einstein added to his equations to balance the push of gravity.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife