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

The calculations of Big Bang nucleosynthesis, which correctly predict the abundances of hydrogen and helium in the Universe, put strict constraints on how much light-emitting matter there can be, and that number simply isn’t large enough to accommodate all these disparate results. —ArsTechnica, 25 June 2025

Barnard's Loop is part of the even bigger Orion molecular cloud complex, made up of dust, hydrogen and helium, and is the birthplace of stars. —Miguel Claro, Space.com, 24 June 2025

So, the hydrogen and helium atoms formed during recombination, when the cooler temperature allowed electrons to fall into orbits. —Stephen L. Levy, The Conversation, 23 June 2025

In the past airships like Zeppelins and blimps used hydrogen but for obvious fiery reasons, helium is now the preferred option. —Trinity Francis, Forbes.com, 20 June 2025

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