Definition of helium
: a light colorless inert gaseous element found especially in natural gases and used chiefly for inflating airships and balloons, in lamps, in cryogenic research, and as a component of inert atmospheres (as in welding) — see element table
Recent Examples of helium from the Web
Follow the flying doughnut Donutology in Westport launched a doughnut into space with the help of a helium weather balloon.
Outside, after the ceremony, there were hugs, helium balloons, smiles and bouquets of bright flowers.
It is blamed for stripping away much of the Martian atmosphere and bombarding the surface of the moon with elements including helium, neon and argon.
With hydrogen ruled out as a buoyant material for obvious reasons, the next best option is helium, which is more expensive and less effective.
Jupiter's atmosphere is around 90 percent hydrogen, for example, and approximately 10 percent helium.
HOW: Deuterium gas is heated to 100 million degrees Celsius, which causes the hydrogen isotopes to break down into plasma and their nuclei to fuse, releasing helium and a free neutron as energy.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'helium'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
Origin and Etymology of helium
New Latin, from Greek hēlios
First Known Use: 1871See Words from the same year
HELIUM Defined for English Language Learners
Definition of helium for English Language Learners
: a chemical element that is a colorless gas, that is lighter than air, and that is often used to fill balloons
HELIUM Defined for Kids
Definition of helium for Students
: a very light gaseous chemical element that is found in various natural gases, will not burn, and is used in balloons
Seen and Heard
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