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 These stars, born from the hydrogen and helium gasses that clouded the early universe, are likely 10 to 100 times larger than our sun and would be found in the furthest reaches of the observable universe. Tim Childers, Popular Mechanics, "Texans Want to Put a Big Ol' Liquid Mirror Telescope on the Moon," 18 Nov. 2020 The hydrogen target is in line with industry demands. Jess Shankleman, Bloomberg.com, "U.K.’s Green Plan Backs 250,000 Jobs and Bans Gas Car Sales," 17 Nov. 2020 The reaction also releases electrons, which, in the presence of carbon dioxide and hydrogen, can make water and formaldehyde. Tim Flannery, The New York Review of Books, "In the Soup," 17 Nov. 2020 If built, the refinery would use hydrogen in a reaction process that turns soybean, canola oil, tallow and used cooking oil into a form of diesel that can substitute for the traditional diesel fuel made from crude oil. Mark Schleifstein, NOLA.com, "Renewable diesel plan aligns with Gov. Edwards' aim to reduce greenhouse gas emissions," 15 Nov. 2020 This substance, a compound of phosphorus and hydrogen, should be able to survive only briefly in an atmosphere like that of Venus. The Economist, "Planetary science Is there really phosphine on Venus?," 14 Nov. 2020 Engineers are working on a problem related to a prevalve that supplies liquid hydrogen to the rocket's RS-25 engines. Eric Berger, Ars Technica, "Rocket Report: SpaceX set for second crew launch, Chinese firm reaches orbit," 13 Nov. 2020 High in the atmosphere, UV light readily splits the water, allowing the hydrogen and oxygen to be lost to space. Paul Voosen, Science | AAAS, "Martian dust storms parch the planet by driving water into space," 12 Nov. 2020 The oxygen continues to break down, while the hydrogen is light enough to flit away from the planet forever. Charlie Wood, Popular Science, "Mars died billions of years ago and its guts are still spilling into space," 12 Nov. 2020

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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Time Traveler for hydrogen

Time Traveler

The first known use of hydrogen was in 1788

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Statistics for hydrogen

Last Updated

22 Nov 2020

Cite this Entry

“Hydrogen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hydrogen. Accessed 28 Nov. 2020.

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More Definitions for hydrogen


How to pronounce hydrogen (audio)

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

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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