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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Other Words from hydrogen

hydrogenous \ hī-​ˈdrä-​jə-​nəs \ adjective

Examples of hydrogen in a Sentence

Recent Examples on the Web

And liquid oxygen and hydrogen are on the mild end. Jonathan M. Gitlin, Ars Technica, "Bloodhound SSC: How do you build a car capable of 1,000mph?," 24 Nov. 2018 The lander’s engines are meant to run on liquid oxygen and liquid hydrogen — the main chemical components of water. Loren Grush, The Verge, "This is Lockheed Martin’s idea for a reusable lander that carries people and cargo to the Moon," 3 Oct. 2018 Launched today just west of Hamburg, the Coradia iLint trains are the very first in the world to create electricity through a chemical reaction between hydrogen and oxygen. Meredith Carey, Condé Nast Traveler, "The World's First Hydrogen-Powered Train Just Arrived in Germany," 17 Sep. 2018 Semi-artificial photosynthesis, a relatively new field of study, aims to address those concerns by combining manmade technologies with biological processes in order to mimic nature’s method of splitting water into oxygen and hydrogen. Fox News, "Scientists invent way to create 'unlimited renewable energy'," 7 Sep. 2018 An electrolyzer uses the current to spilt the water into hydrogen and oxygen. Jack Stewart, WIRED, "The Funky Boat Circling the Planet on Renewable Energy and Hydrogen Gas," 5 July 2018 Ice harvested from the moon can be used to replenish oxygen supplies on the station, produce hydrogen fuel for spacecraft, and give astronauts fresh water to drink. Avery Thompson, Popular Mechanics, "Lockheed Martin Unveils Design for Lunar Lander," 3 Oct. 2018 Earlier this year, for example, NASA announced that Saturn’s moon Enceladus could support life thanks to the discovery of hydrogen. Chris Ciaccia, Fox News, "Alien life on Saturn's moon? Dust storms on Titan spotted for the first time," 25 Sep. 2018 Unlike America, which gets most of its carbon dioxide from natural wells, 50% of Europe’s comes as a by-product of ammonia production; a further 30% stems from processes for making hydrogen and bioethanol. The Economist, "Shortages of carbon dioxide in Europe may get worse," 5 July 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

2 Jan 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 \

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 \

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 \ 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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