ra·​tio | \ˈrā-(ˌ)shō, -shē-ˌō\
plural ratios

Definition of ratio 

1a : 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

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Synonyms for ratio


proportion, rate

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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

Some analysts say the low ratio indicates investors are boosting holdings of options that pay out when the underlying shares gain. Gunjan Banerji, WSJ, "Good News for Stocks? Options Investors Eye December Rally," 3 Dec. 2018 The ratio of shoppers to bona fide employees is over 116 to 1. Cyrus Farivar, Ars Technica, "Instacart changes how it pays shoppers, but many say they’re now making less," 18 Nov. 2018 In the long term, if it ... As AI gets probably much smarter than humans, the relative intelligence ratio is probably similar to that between a person and a cat, maybe bigger. Eric Johnson, Recode, "Full Q&A: Tesla and SpaceX CEO Elon Musk on Recode Decode," 2 Nov. 2018 Indeed, the mass ratio is similar for our own Earth-moon system — 1.2 percent. Mike Wall, Space.com, "First Exomoon Found? Neptune-Sized World Possibly Spotted Orbiting Alien Planet," 3 Oct. 2018 In Catalonia, the ratio currently stands at 6.7 to one. Fox News, "Striking taxi drivers clog Spain's streets to protest growth of ride-hailing apps," 30 July 2018 Half of the French and Belgian squads' players trace their ancestry to Africa, a much higher percentage than the ratio of immigrants in either country. Ishaan Tharoor, Washington Post, "The World Cup is a victory for the immigrant dream," 12 July 2018 Using soap could upset your vagina’s ratio of good to bad bacteria, possibly resulting in infections such as bacterial vaginosis. Sophie Saint Thomas, SELF, "Here's Exactly What to Do If You Get Something Spicy on Your Vulva or Vagina," 12 Oct. 2018 The Heat has cast him as a backup point guard at times and his assist-to-turnover ratio improved to 3.2-to-1.2 two seasons ago before slipping to 2.3-to-1.1 last season. Barry Jackson, miamiherald, "Tyler Johnson contract creating challenges, and these interesting future options for Heat," 12 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ratio.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of ratio

1660, in the meaning defined at sense 1a

History and Etymology for ratio

Latin, computation, reason — more at reason

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Statistics for ratio

Last Updated

11 Dec 2018

Look-up Popularity

Time Traveler for ratio

The first known use of ratio was in 1660

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More Definitions for ratio



English Language Learners Definition of ratio

: the relationship that exists between the size, number, or amount of two things and that is often represented by two numbers


ra·​tio | \ˈrā-shō, -shē-ˌō\
plural ratios

Kids Definition of ratio

: the relationship in number or quantity between two or more things the ratio of teachers to students


ra·​tio | \ˈrā-(ˌ)shō, -shē-ˌō \
plural ratios

Medical Definition of ratio 

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

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More from Merriam-Webster on ratio

Rhyming Dictionary: Words that rhyme with ratio

Thesaurus: All synonyms and antonyms for ratio

Spanish Central: Translation of ratio

Nglish: Translation of ratio for Spanish Speakers

Britannica English: Translation of ratio for Arabic Speakers

Britannica.com: Encyclopedia article about ratio

Comments on ratio

What made you want to look up ratio? Please tell us where you read or heard it (including the quote, if possible).


to make faulty or ineffective

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