: 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
But that was before NASA discovered that the Starliner spacecraft had experienced multiple helium leaks and propulsion system issues.
—
Eric Lagatta, USA TODAY, 8 Mar. 2025
Dense clumps of primordial hydrogen and helium left over from the big bang collapsed under their own gravitational weight, igniting thermonuclear chain reactions at their cores that would light up the universe for the first time.
—Conor Feehly, Scientific American, 4 Mar. 2025
The end of the fusion of hydrogen to helium also cuts off the outward energy that supports stars against the inward push of their own gravity.
—Robert Lea, Space.com, 20 Feb. 2025
The Infinity technology will be used to insulate its helium tank against temperatures that are expected to range between 250 degrees above or below zero.
—Jean E. Palmieri, WWD, 19 Feb. 2025
See All Example Sentences for helium
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Eric Lagatta, USA TODAY, 8 Mar. 2025
Dense clumps of primordial hydrogen and helium left over from the big bang collapsed under their own gravitational weight, igniting thermonuclear chain reactions at their cores that would light up the universe for the first time.
—Conor Feehly, Scientific American, 4 Mar. 2025
The end of the fusion of hydrogen to helium also cuts off the outward energy that supports stars against the inward push of their own gravity.
—Robert Lea, Space.com, 20 Feb. 2025
The Infinity technology will be used to insulate its helium tank against temperatures that are expected to range between 250 degrees above or below zero.
—Jean E. Palmieri, WWD, 19 Feb. 2025
See All Example Sentences for helium
Articles Related to helium
Cite this Entry
“Helium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/helium. Accessed 24 Mar. 2025.
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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
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