Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “diameter”


noun [C/U]  /dɑɪˈæm·ɪ·t̬ər/ us  
geometry the distance from one side to the opposite side of a circle, measured by a line passing through the center of the circle: [C] We need a pipe with a diameter of about six inches.
(Definition of diameter from the Cambridge Academic Content Dictionary © Cambridge University Press)
What is the pronunciation of diameter?
Add Cambridge dictionaries to your browser to your website

Definitions of “diameter” in other dictionaries

Word of the Day


to throw or drop something carelessly

Word of the Day


Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More