hydrogen

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

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

See hydrogen defined for English-language learners

See hydrogen defined for kids

Recent Examples of hydrogen from the Web

Robert Pease, president of the Northwest Suburban Astronomers, set up a hydrogen alpha telescope linked to a television monitor during the event – a sight that attracted a crowd of more than 25 people.

— phil rockrohr, chicagotribune.com, "Residents line up early to catch glimpse of solar eclipse in Arlington Heights," 21 Aug. 2017
Then, the solid carbon and hydrogen crystals fall deep into the interior of the planets.

— avery thompson, Popular Mechanics, "Scientists Simulate Neptune's Mythical Diamond Rain," 21 Aug. 2017
But the dearth of hydrogen fueling stations is an obstacle for mass adoption.

— youkyung lee, The Seattle Times, "Hyundai unveils new fuel cell SUV with longer travel range," 17 Aug. 2017
Breaking that ice down into oxygen and hydrogen would provide rocket fuel that would cut the price of operating in deep space.

— lee roop, AL.com, "Trump said ready to name U.S. Rep. Jim Bridenstine NASA boss," 17 Aug. 2017
The magnesium reacts with the acid, neutralizing it and causing the release of hydrogen bubbles, which propel the micromotors.

— bradley j. fikes, sandiegouniontribune.com, "Micromotors neutralize stomach acid, deliver antibiotic," 16 Aug. 2017
From these neutron counts, scientists can infer the amount of hydrogen—and thus, presumably, the amount of water—present in the uppermost meter or so of soil.

— sid perkins, Science | AAAS, "Water ice found near Mars’s equator could entice colonists and life-seekers," 16 Aug. 2017
Most of the material was hydrogen and helium, but some of it was made up of leftover remnants from the violent deaths of stars.

— valerie strauss, Washington Post, "Facts about our sun and moon that you’re embarrassed to admit you don’t know," 9 Aug. 2017
At the top of many tanks accumulates a hydrogen gas, which, if not vented, might cause the tank to explode.

— michael lewis, The Hive, "Why the Scariest Nuclear Threat May Be Coming from Inside the White House," 2 Aug. 2017

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

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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

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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

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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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