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

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

Typhur’s new Sync appliances change that equation entirely. —Matt Emma, USA Today, 12 Sep. 2025

The first prediction, devised by New Zealand mathematician Roy Kerr in 1963, builds upon Einstein’s theory of general relativity, and states that black holes should be paradoxically simple objects, described by a single equation. —Jacopo Prisco, CNN Money, 11 Sep. 2025

Attribution could flip that equation, creating revenue streams for operators who feed data into collective intelligence models that optimize grids, cut waste, and prevent blackouts. —Roomy Khan, Forbes.com, 11 Sep. 2025

On the other side of the equation, the Chiefs’ receiving corps has looked eerily familiar. —Pete Sweeney, Kansas City Star, 11 Sep. 2025

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