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

In a note to clients published this week, Higgins found that for information technology and the rest of Big Tech, the ratio of the current share price to earnings per share has risen over the last few years, showing inflated valuations. —Sasha Rogelberg, Fortune, 29 Mar. 2026

Seven locations also showed chlorine-to-sulfate mass ratios high enough to signal elevated corrosion potential — a condition that can increase the likelihood that metals will leach from plumbing over time. —Bridget Shirvell, Hartford Courant, 29 Mar. 2026

The three stood as the only players with better than a 4-to-1 ratio. —Ira Winderman, Sun Sentinel, 29 Mar. 2026

With 24-31 grams of protein per 100 g, the leanest of all meats provides the best ratio of protein to fat. —Philipp Wehsack, Vogue, 28 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