ratio

noun

ra·​tio ˈrā-shē-ˌō 

-(ˌ)shō

plural ratios

1

a

: the indicated quotient of two mathematical expressions

b

: the relationship in quantity, amount, or size between two or more things : proportion

2

: the expression of the relative values of gold and silver as determined by a country's currency laws

Synonyms of ratio

• rate

Examples of ratio in a Sentence

What is the length-to-width ratio?

the ratio of students to teachers in the school is nine to one

Recent Examples on the Web

Cardholders who pay their balances in full and on time and keep their utilization rate — or the ratio of debt to total credit — below 30% of their available credit can boost their credit score. —Stephanie Dhue,sharon Epperson,jessica Dickler, CNBC, 12 Jan. 2026

MacFann said the district's goal is to maintain an overall attendance ratio. —Barry Pintar, CBS News, 12 Jan. 2026

While recyclers also must clearly communicate their material specifications—such as fiber ratios, contamination thresholds and formatting needs—brands can, through design choices like standardized fiber blends and trim simplification, improve end-of-life recyclability. —Jasmin Malik Chua, Sourcing Journal, 12 Jan. 2026

There were even multiple catchy jingles that captured the correct ratios for each component, though different versions included varying amounts. —Jasmine Smith, Southern Living, 12 Jan. 2026

Word History

Etymology

Latin, computation, reason — more at reason entry 1

First Known Use

1660, in the meaning defined at sense 1a

Phrases Containing ratio

• aspect ratio
• case fatality ratio
• common ratio
• focal ratio
• golden ratio
• gyromagnetic ratio
• loss ratio
• nutritive ratio
• Poisson's ratio
• price-earnings ratio
• ultima ratio

Rhymes for ratio

• acknow
• aglow
• ago
• airglow
• aloe
• altho
• although
• ammo
• backflow
• backhoe
• banjo
• barbeau

Kids Definition

ratio

noun

ra·​tio ˈrā-shō 

-shē-ˌō

plural ratios

1

: the quotient of two numbers or mathematical expressions

the ratio of 6 to 3 may be expressed as 6:3, ⁶⁄₃, and 2

2

: the relationship in quantity, amount, or size between two or more things

women outnumbered men in the ratio of three to one

Medical Definition

ratio

noun

ra·​tio ˈrā-(ˌ)shō, -shē-ˌō 

plural ratios

: the relationship in quantity, amount, or size between two or more things see sex ratio