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

Wes Harrell, a broker and head of a trading group at capital markets firm Seaport Global, told Fortune that in these instances, the loan-to-value ratio of potential refunds used as collateral might be about 50%, meaning a $10 million refund claim would only be worth $5 million as a loan. —Sasha Rogelberg, Fortune, 12 Apr. 2026

In Irvine, the parkland ratio is about 27%, according to the 2025 City Park Facts report by the Trust for Public Land, a nonprofit aimed at developing and preserving urban open space. —Andre Mouchard, Oc Register, 12 Apr. 2026

Any effort to shed weight where possible is key to an aircraft’s power-to-weight ratio. —Christopher McFadden, Interesting Engineering, 12 Apr. 2026

Contrast ratio is defined as the difference between the brightest white tones and the darkest blacks. —Tony Hoffman, PC Magazine, 11 Apr. 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