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

Farrell’s turn feels less like a full-blooded human and more like just one part of a complex equation — which is in keeping with the highly structured and allegorical nature of Allen’s film. —Bilge Ebiri, Vulture, 30 Oct. 2025

Density concerns But part of that equation might include higher density developments, a path that concerns many residents on the west side, Rainey said. —Taylor O'Connor, Kansas City Star, 29 Oct. 2025

Harden’s brilliance was only one part of the equation. —Joseph Dycus, Mercury News, 29 Oct. 2025

Soaring cocoa prices in recent years have changed the equation for many chocolate makers. —Melinda Yao, NBC news, 29 Oct. 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