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

Inventory loosening up One sign the housing market is loosening is an increasing ratio of sellers to buyers. —Mary Cunningham, CBS News, 6 Mar. 2026

The restaurants were selected by members of the Courier Journal newsroom based on various criteria, including taste, texture, cheese and topping to chip (or tot) ratio, creativity, flavor, and more. —Amanda Hancock, Louisville Courier Journal, 6 Mar. 2026

This ratio will almost certainly get more skewed toward Starlink, too; back in 2019, when the first Starlink satellites were launched, SpaceX filed with the Federal Communications Commission (FCC) for up to 30,000 additional satellites. —Phil Plait, Scientific American, 6 Mar. 2026

This sheet pan version of the classic wins by cooking faster and providing a generous ketchup-to-loaf ratio. —Josh Miller, Southern Living, 6 Mar. 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