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

• proportion
• 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

This is not a conservative investment, but the risk/reward ratio looks good to me. —John Dorfman, Forbes.com, 28 Apr. 2025

This is a slightly moving target because of the variable ABV of the spirit—a 40 percent whisky will need less sweetness than a 45 or 50 percent whisky—so the above ratio is a guideline based on a 40 or 43 percent scotch. —Jason O'Bryan, Robb Report, 26 Apr. 2025

Lastly, the ratio of the last 12-month earnings per share to indicated next 12-month dividend per share must be greater than 1.0. —Michelle Fox, CNBC, 25 Apr. 2025

The ratio of the masses of the planet to its host star is roughly twice that of the Earth to the Sun. —John Timmer, ArsTechnica, 25 Apr. 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