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

Homecoming has a dun color palette but still manages to be strangely beautiful to look at, full of faceted set compositions and a clever shift in camera ratio to signal jumps in time. Taylor Antrim, Vogue, "The Unsettling, Paranoia-Inducing Homecoming Is Your Next TV Binge," 2 Nov. 2018 There’s also an in-display fingerprint sensor, as if this phone wasn’t on-trend enough, resulting in a screen-to-body ratio of just over 95 percent. Jon Porter, The Verge, "Lenovo’s Z5 Pro is a cheaper take on the slider phone trend," 1 Nov. 2018 That decrease has pushed San Diego to 16th among the country’s 20 largest cities in the ratio of housing units per person, roughly 20 percent behind national leaders Seattle and Atlanta. David Garrick, sandiegouniontribune.com, "San Diego officials say new housing study will help them find solutions to crisis," 1 July 2018 One Vanguard Group study noted that a 110 basis-point expense ratio can cost as much as 25% of total returns after 30 years. Barry Ritholtz, latimes.com, "Ranking the factors that help or hurt your investment returns," 14 June 2018 By comparison, some low-cost index funds have expense ratios under 0.05 percent. Daniel Gilbert, The Seattle Times, "After investigation into Seattle’s pension system, readers wonder: Why not just invest in index funds?," 16 May 2018 The calculator then divides the calories into carbs, protein, and fat in different ratios depending on the diet. Dylan Mackay, SELF, "Here's How to Tell If You Should Be Tracking Your Macros," 14 May 2018 Such changes are detectable in changes in the carbon isotope ratio between biological and inorganic carbon—that is, between the carbon incorporated into things like seashells and that which goes instead into lifeless volcanic rock. Steven Ashley, Scientific American, "Could an Industrial Prehuman Civilization Have Existed on Earth Before Ours?," 23 Apr. 2018 In its lighter, fluffier incantation, it’s cooked in a 2:1 ratio of liquid to millet. Ashleigh Spitza, Milwaukee Journal Sentinel, "Millet, the underdog of grains, packs a punch of nutrients," 11 Apr. 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

20 Feb 2019

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).


excited commotion or publicity

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