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

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

This construction, paired with an automatic helium escape valve integrated into the crown, allows the watch to endure prolonged saturation diving without damaging its seals or movement. —Matthew Catellier, Forbes.com, 30 Aug. 2025

The researchers focused on a merger of two hybrid white dwarfs — stellar remnants with carbon-oxygen cores wrapped in thick shells of helium, likely shaped by earlier interactions with companion stars. —Sharmila Kuthunur, Space.com, 29 Aug. 2025

In the first stars, hydrogen atoms fused together to create helium. —ArsTechnica, 27 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