helium

noun

he·​li·​um ˈhē-lē-əm 

ˈhēl-yəm

: a chemical element of the noble gas group with atomic number 2 that is found especially in natural gases and used chiefly for inflating airships and balloons, as a coolant for superconductors, and as a component of inert atmospheres (as in welding)

—often used before another noun

helium balloons

helium gas

see Chemical Elements Table

Examples of helium in a Sentence

Recent Examples on the Web

This study was done at temperatures so low that even helium turns liquid. — Neetika Walter, Interesting Engineering, 5 Sep. 2026

Reactors can also require millions of gallons of water to stay cool, though advanced reactors can use other cooling materials such as liquid metals, liquid salts, or helium gas. — Donald Keough, Christian Science Monitor, 2 Sep. 2026

Also, there was no evidence of metals or any element other than hydrogen and helium in the spectrum. — ArsTechnica, 1 Sep. 2026

This revealed that the globular clusters at the heart of our galaxy can be categorized in three distinct ways based upon their age and their metallicity, a measure of elements heavier than hydrogen and helium, which astronomers refer to as metals. — Robert Lea, Space.com, 24 Aug. 2026

Word History

Etymology

New Latin, from Greek hēlios

First Known Use

1871, in the meaning defined above

Rhymes for helium

• cilium

Kids Definition

helium

noun

he·​li·​um ˈhē-lē-əm 

: a light colorless nonflammable element that is found in various natural gases and is used especially to blow up balloons see element

Medical Definition

helium

noun

he·​li·​um ˈhē-lē-əm 

: a light colorless nonflammable gaseous element found especially in natural gases and used chiefly for inflating airships and balloons, for filling incandescent lamps, and for cryogenic research

—symbol He see Chemical Elements Table