equation

noun

equa·​tion i-ˈkwā-zhən 

also -shən

1

a

: the act or process of equating

b(1)

: an element affecting a process : factor

(2)

: a complex of variable factors

c

: a state of being equated

specifically : a state of close association or identification

To bring governmental enterprises and payment for them into immediate equation …

—R. G. Tugwell

2

a

: a usually formal statement of the equality or equivalence of mathematical or logical expressions

b

: an expression representing a chemical reaction quantitatively by means of chemical symbols

Examples of equation in a Sentence

the equation of material wealth with happiness

Recent Examples on the Web

But charging an electric vehicle is not necessarily free either, and there are other costs to consider in the overall equation, such as higher sticker price and faster depreciation. —Becca Stanek, TheWeek, 29 Apr. 2026

Effortless durability meets elevated style in these pieces that take constant upkeep out of the equation. —Maria Sabella, Better Homes & Gardens, 29 Apr. 2026

This is where Physical AI changes the equation. —Mrigakshi Dixit, Interesting Engineering, 29 Apr. 2026

Give us an equation for your show. —Michael Schneider, Variety, 27 Apr. 2026

Word History

First Known Use

14th century, in the meaning defined at sense 1a

Phrases Containing equation

• characteristic equation
• cubic equation
• differential equation
• Diophantine equation
• enter (into) the equation
• equation of time
• linear equation
• parametric equation
• partial differential equation
• personal equation
• quadratic equation
• Schrödinger equation
• simple equation
• wave equation

Rhymes for equation

• abrasion
• caucasian
• eurasian
• evasion
• invasion
• occasion
• persuasion
• asian
• suasion
• athanasian

Kids Definition

equation

noun

equa·​tion i-ˈkwā-zhən 

also -shən

1

: the act or process of equating : the state of being equated

2

a

: a statement of the equality of two mathematical expressions

b

: an expression involving chemical symbols for a chemical reaction

Medical Definition

equation

noun

equa·​tion

i-ˈkwā-zhən also -shən

: an expression representing a chemical reaction quantitatively by means of chemical symbols