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

The ratio of nickel to cobalt in these particles matched that of nickel, manganese and cobalt battery cathodes, clearly linking the contamination to the fire. —Ivano W. Aiello, The Conversation, 1 Dec. 2025

Men with higher waist-to-hip ratios showed a pattern of thicker heart muscles and smaller internal chamber volume. —Khloe Quill, FOXNews.com, 1 Dec. 2025

This unusually high power-to-weight ratio allows the propulsor to meet the extreme demands of supersonic airflow. —Georgina Jedikovska, Interesting Engineering, 1 Dec. 2025

All places that cold air could enter are sealed up tightly, and the coat is packed with ethically sourced down filling rated at 700+, which is considered an excellent warmth-to-weight ratio. —Olivia Young, Travel + Leisure, 1 Dec. 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

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