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

After Starliner arrived at the space station, NASA and Boeing worked for weeks to better understand the problems — including helium leaks and propulsion issues — that plagued the first leg of the test flight. —Jackie Wattles, CNN, 11 Feb. 2025

But the Starliner, built as part of a NASA program to develop independent commercial crew ships to ferry astronauts to and from the space station, ran into propulsion problems and helium leaks shortly after launch that prompted weeks and then months of tests and analysis. —William Harwood, CBS News, 7 Feb. 2025

Instead, the Starliner spacecraft suffered problems with overheating thrusters and helium leaks after its launch last June aboard an Atlas V rocket. —Stephen Clark, Ars Technica, 4 Feb. 2025

With hydrogen and some helium gas pervading the cosmos, there was nothing much around to make light. —The Editors, JSTOR Daily, 30 Jan. 2025

Word History

Etymology

New Latin, from Greek hēlios

First Known Use

1871, in the meaning defined above

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