hydrogen

noun hy·dro·gen \ ˈhī-drə-jən , -dər- \

|Updated on: 14 Aug 2018

Definition of hydrogen

: a nonmetallic element that is the simplest and lightest of the elements, is normally a colorless odorless highly flammable diatomic gas, and is used especially in synthesis — see Chemical Elements Table — compare deuterium, tritium

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hydrogenous

play \hī-ˈdrä-jə-nəs\ adjective

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See hydrogen defined for kids

Recent Examples of hydrogen from the Web

If a hydrogen atom were the size of Earth, the proton at its center would fit inside the Ohio State football stadium.

— author: sarah kaplan, Anchorage Daily News, "In a cosmic first, scientists detect ‘ghost particles’ from a distant galaxy," 12 July 2018
If a hydrogen atom were the size of Earth, the proton at its center would fit inside the Ohio State football stadium.

— sarah kaplan, chicagotribune.com, "In a cosmic first, scientists detect 'ghost particles' from a distant galaxy," 12 July 2018
The states also want further adoption of hydrogen fuel cell vehicles, though that technology has received less emphasis from auto makers than electric cars.

— mike spector, WSJ, "California and Eight Other States Push Plan to Boost Zero-Emission Vehicles," 20 June 2018
Water molecules are made up of one oxygen atom and two hydrogen atoms.

— megan arnett, Scientific American, "Mix It Up with Oil and Water," 24 May 2018
This week, Bloomberg Technology’s Jing Cao visits the researchers who are smashing hydrogen atoms together in a process called nuclear fusion.

— Bloomberg.com, "The Nuclear Tech Breakthrough That Could Make Oil Obsolete," 21 Aug. 2017
Deuterium is a naturally occurring, stable isotope of the element hydrogen.

— kevin davenport, idahostatesman, "Yellowstone's magma chamber is more powerful than we knew. Here's why studying it matters.," 3 July 2018
At the same time, Jupiter may have hurled material inward as well, crashing hydrogen-rich asteroids and planetary embryos, or planetesimals, into crowded young terrestrial planets.

— nola taylor redd, Smithsonian, "How Jupiter May Have Gifted Early Earth With Water," 20 June 2018
Here’s the problem with finding that missing matter: It would be mostly made out of hydrogen, the simplest element and by far the most abundant in the universe.

— amina khan, latimes.com, "After years of searching, scientists can finally account for all the normal matter in the universe," 20 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'hydrogen.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of hydrogen

French hydrogène, from hydr- + -gène -gen; from the fact that water is generated by its combustion

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First Known Use: 1788

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HYDROGEN Defined for English Language Learners

hydrogen

noun

Definition of hydrogen for English Language Learners

: a chemical element that has no color or smell and that is the simplest, lightest, and most common element

HYDROGEN Defined for Kids

hydrogen

noun hy·dro·gen \ ˈhī-drə-jən \

Definition of hydrogen for Students

: a colorless, odorless, and tasteless flammable gas that is the lightest of the chemical elements

History for hydrogen

When hydrogen is burned it combines with oxygen to make water. That fact accounts for the name of this gas. The word hydrogen was formed from two Greek roots. The first, hydro-, means “water,” and the second, -gen, means “giving rise to, producing.”

Medical Dictionary

hydrogen

noun hy·dro·gen \ ˈhī-drə-jən \

medical Definition of hydrogen

: 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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