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

While most tidal effects were easily canceled out with the combination of data from the two satellites, one lunisolar tide called K1 brought uncertainty into the equation. — Mary Randolph, Scientific American, 8 July 2026

When social platforms including Facebook, TikTok, and Instagram are added to the equation, 61% of listeners attribute discovering their favorite podcast to either YouTube or social media. — Frank Racioppi, Forbes.com, 7 July 2026

The price equation If OPEC turns the spigots to max, a complex operation with no guarantee of success, all that oil may have nowhere to go. — David Goldman, CNN Money, 6 July 2026

The evidence-free governance theorists dangerously ignore the value of wisdom from actual experience beyond misleading abstract mathematical equations which neglect the genuine impact of leaders. — Jeffrey Sonnenfeld, Fortune, 6 July 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