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

Very few heavier elements are present in the Sun’s photosphere, and hence cosmic rays are extraordinarily unlikely to hit them, being much more likely to hit a proton, electron, or a helium nucleus. —Ethan Siegel, Big Think, 4 Sep. 2025

Instead of splitting heavy atoms like uranium or plutonium to release energy, fusion works by fusing hydrogen atoms to form helium for energy. —New Atlas, 2 Sep. 2025

Boxy autonomous vehicles scrape up the top layer of lunar dirt and crush it to release gas containing a valuable form of helium. —Jeremy Bogaisky, Forbes.com, 2 Sep. 2025

These frozen pellets are accelerated using a high-pressure pulse of helium gas, injecting them deep into the stellarator’s 30-million-degree plasma core. —Aman Tripathi, Interesting Engineering, 30 Aug. 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