equation

The word “equation” means a mathematical statement that two expressions are equal, usually written with an equals sign. In plain terms, a math statement showing two things are equal — or, more loosely, all the factors that go into a decision or problem.

“Equation” is pronounced ih-KWAY-zhuhn (/ɪˈkweɪ.ʒən/ in IPA).

Here is “equation” used in a sentence: “She solved the equation for x.”

“Equation” is a noun.

The word “equation” comes from Latin. From Latin aequatio, "an equalizing," from aequare ("to make equal").

“Equation” is a fairly common word in modern English, usually learned at around the B2 level.

“Equation” has 2 distinct senses listed in this dictionary. The most common is: a mathematical statement that two expressions are equal, usually written with an equals sign.

An equation is a mathematical statement that two expressions are equal, and it always contains an equals sign, as in 2x + 1 = 7. An expression, such as 2x + 1 on its own, has no equals sign and simply names a value rather than stating something that can be true or false.

A formula is a rule or relationship expressed in symbols and meant to be reused, such as A = πr² for the area of a circle. An equation is any statement that two expressions are equal, including one-off problems to solve, such as 3x = 12, so most formulas are equations but not every equation is a formula.

An equation states that two expressions are equal and is written with an equals sign. An inequality states that one expression is greater than or less than another, using symbols such as <, >, ≤, or ≥ instead.