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

Experts examined the needles using mass spectrometry, which measures molecules’ mass-to-charge ratio, and an imaging technique called micro-CT scanning. —Julia Binswanger, Smithsonian Magazine, 11 Dec. 2024

The company’s medical care ratio has increased from 82.6% in 2021 to 84.9% for the last twelve-month period. —Trefis Team, Forbes, 11 Dec. 2024

Apple’s forward price-to-earnings ratio averaged 26.5 times over the past five years. —Morgan Chittum, CNBC, 11 Dec. 2024

The ratio reached 3:1 for the first time in 2018 and hit a peak in 2022, when the median home price was 3.9 times the median income. —Sami Sparber, Axios, 9 Dec. 2024

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

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