Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “helium”


noun [U]     /ˈhiː.li.əm/ (symbol He)
a chemical element that is a gas lighter than air, that will not burn and is used in balloons, airships, and some types of lightsChemical elements
(Definition of helium noun from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
Focus on the pronunciation of helium

Definitions of “helium” in other dictionaries

Word of the Day


friendly or helpful

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