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

Intentions are only part of the equation, the rest are actions, and actions speak louder than words. —Omer Awan, Forbes.com, 3 May 2025

Yes, there should be a teapot in the equation, but the real draw is the spread: a slew of tiny sandwiches; sweet and buttery pastries (like Bon Appétit Bake Club’s Coffee Cake Scones); and the extravagance of fancy china, teacups, and a tiered pastry stand for good measure. —Oset Babür-Winter, Bon Appetit Magazine, 1 May 2025

The subtraction is only to prevent double-counting, though, since those purchases are already covered in the other terms of the equation. —The Editors, National Review, 1 May 2025

Trump administration policies including tariffs will likely factor into the equation. —Brian Niemietz, New York Daily News, 1 May 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