hy·​dro·​gen | \ ˈhī-drə-jən How to pronounce hydrogen (audio) , -dər-\

Definition of hydrogen

: 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 — see Chemical Elements Table — compare deuterium, tritium

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Other Words from hydrogen

hydrogenous \ hī-​ˈdrä-​jə-​nəs How to pronounce hydrogenous (audio) \ adjective

Examples of hydrogen in a Sentence

Recent Examples on the Web

If conditions on Mars aren't what SpaceX expects in terms of resource availability, Wooster said SpaceX is considering bringing components of fuel to Mars for the return trip, likely in the form of either water or pure hydrogen. Ben Pearson, Ars Technica, "SpaceX beginning to tackle some of the big challenges for a Mars journey," 3 June 2019 General Motors plans a Cadillac electric vehicle in 2021, and more than 20 that run on batteries or hydrogen in four years. Tom Krisher, The Seattle Times, "Detroit show has SUVs, horsepower, but electric cars are few," 14 Jan. 2019 Praxair, Danbury, $11.4B The industrial gas supplier Praxair Inc. distributes products including oxygen, helium, nitrogen and hydrogen for a variety of uses. Russell Blair, courant.com, "These 16 Fortune 500 Companies Are Headquartered In Connecticut," 23 May 2018 The mission would have involved sending a robot to the moon’s polar region in 2022 to probe for things like underground water and hydrogen. Sarah Gray, Fortune, "NASA Cancels Moon Mission, Frustrating Scientists," 27 Apr. 2018 Bezos said the lander will be able to transport between 3.6 to 6.5 tons of cargo and will run on liquid hydrogen. Matt Blitz, Popular Mechanics, "Blue Origin Reveals the Blue Moon Lunar Lander," 9 May 2019 The space station’s outdated nickel-hydrogen batteries are being replaced with lithium-ion batteries, a lengthy process spanning years. Marcia Dunn, The Seattle Times, "Spacewalking astronauts install better station batteries," 3 Apr. 2019 But hydrogen is commonly produced from natural gas heated by steam, which results in greenhouse gas emissions and other environmental problems. Melissa C. Lott, Scientific American, "This Advance Brings Us a Lot Closer to a "Hydrogen Economy"," 1 May 2017 Some of this airborne table salt reacts chemically with hydrogen in the water vapor, creating the hydrochloric acid. Nsikan Akpan, Scientific American, "Kilauea’s Lava Is Now Spilling into the Ocean. Here’s Why That’s Dangerous," 22 May 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.

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First Known Use of hydrogen

1788, in the meaning defined above

History and Etymology for hydrogen

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

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Statistics for hydrogen

Last Updated

19 Jun 2019

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Time Traveler for hydrogen

The first known use of hydrogen was in 1788

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More Definitions for hydrogen



English Language Learners Definition of hydrogen

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


hy·​dro·​gen | \ ˈhī-drə-jən How to pronounce hydrogen (audio) \

Kids Definition of hydrogen

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


hy·​dro·​gen | \ ˈhī-drə-jən How to pronounce hydrogen (audio) \

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

Other Words from hydrogen

hydrogenous \ hī-​ˈdräj-​ə-​nəs How to pronounce hydrogenous (audio) \ adjective

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More from Merriam-Webster on hydrogen

Spanish Central: Translation of hydrogen

Nglish: Translation of hydrogen for Spanish Speakers

Britannica English: Translation of hydrogen for Arabic Speakers

Britannica.com: Encyclopedia article about hydrogen

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