hydrogen
noun
hy·dro·gen
ˈhī-drə-jən 
-dər-
: a nonmetallic gaseous chemical element with atomic number 1 that is the simplest and lightest of the elements and that is used especially in the processing of fossil fuels and the synthesis of ammonia
—often used before another noun
hydrogen gas
hydrogen atoms
a hydrogen vehicle
the hydrogen industry
see Chemical Elements Table compare deuterium, tritium
Examples of hydrogen in a Sentence
Recent Examples on the Web
The facility represents a pivotal advancement in the transition to renewable hydrogen and low-carbon fuels.
—
David Blekhman, Forbes.com, 9 July 2025
Lithium was the heaviest element to be produced in the Big Bang, which also generated hydrogen and helium.
—Keith Cooper, Space.com, 8 July 2025
The race for global leadership in hydrogen is underway — and the United States is dangerously close to falling behind.
—Heather Reams, Sun Sentinel, 7 July 2025
The grant, along with over $1 billion from Cleveland-Cliffs, would allow the company to install new furnaces that run on a mix of hydrogen and natural gas rather than coal.
—Victoria Moorwood, The Enquirer, 3 July 2025
See All Example Sentences for hydrogen
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David Blekhman, Forbes.com, 9 July 2025
Lithium was the heaviest element to be produced in the Big Bang, which also generated hydrogen and helium.
—Keith Cooper, Space.com, 8 July 2025
The race for global leadership in hydrogen is underway — and the United States is dangerously close to falling behind.
—Heather Reams, Sun Sentinel, 7 July 2025
The grant, along with over $1 billion from Cleveland-Cliffs, would allow the company to install new furnaces that run on a mix of hydrogen and natural gas rather than coal.
—Victoria Moorwood, The Enquirer, 3 July 2025
See All Example Sentences for hydrogen
Cite this Entry
“Hydrogen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hydrogen. Accessed 20 Jul. 2025.
Copy CitationKids Definition
hydrogen
noun
hy·dro·gen
ˈhī-drə-jən
: a chemical element that is the simplest and lightest of all chemical elements and is normally found alone as a colorless odorless highly flammable gas having two atoms per molecule see element
Etymology
from French hydrogène "hydrogen," from hydr- "water" and -gène "producer"; so called because when hydrogen gas burns, it combines with oxygen to produce water
Medical Definition
hydrogen
noun
hy·dro·gen
ˈhī-drə-jən
: a nonmetallic element that is the simplest and lightest of the elements and that is normally a colorless odorless highly flammable diatomic gas
—symbol H
see deuterium, tritium Chemical Elements Table
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