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

That data allowed scientists to map out ratios of strontium isotopes in seawater over time. —Bruce J. MacFadden, The Conversation, 3 Feb. 2025

While administrative positions have grown by 9%, faculty numbers have shrunk by 14%, creating the highest student-faculty ratio among nine comparable state colleges. —Andrea Apa, Sun Sentinel, 31 Jan. 2025

The company maintained a leverage ratio of 6.3, with total equity of $10.23 billion. —Quartz Intelligence Newsroom, Quartz, 28 Jan. 2025

Now, a higher P/S ratio for high-growth companies seems justified. —Trefis Team, Forbes, 27 Jan. 2025

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