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

• 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

Trading close to $270, CRM’s P/S ratio of 6.7x is below its three-year average of 8.6x. —Trefis Team, Forbes.com, 27 June 2025

As the ratio of retiree to workers changes these programs become financially insolvent. —Jasmine Laws, MSNBC Newsweek, 26 June 2025

Despite the rally, the ratio of bullish versus bearish outlooks for the market remains below the historical average, Ed Yardeni, president of Yardeni Research, said in a note. —John Towfighi, CNN Money, 26 June 2025

In the first quarter, Citi’s efficiency ratio in each of its core business units declined versus the year ago quarter, Poonawala said. —Luisa Beltran, Fortune, 26 June 2025

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