hydrogen

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

Updated on: 11 Apr 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

One key test of matter-antimatter symmetry is to compare the frequencies of light absorbed by hydrogen and antihydrogen atoms.

— adrian cho, Science | AAAS, "Atoms and antiatoms haven’t crashed Albert Einstein’s theory of relativity—yet," 4 Apr. 2018
Options for vessel operators may include using clean-burning fuels like methanol, hydrogen and ammonia, as well as implementing electric propulsion, hull design improvements and slower sailing speeds.

— costas paris, WSJ, "Maritime Regulator Seeks to Overcome Deep Divisions on Shipping Emissions," 3 Apr. 2018
Carbon, oxygen and hydrogen are also important nutrients and come to plants via air and water.

— amy hall, sandiegouniontribune.com, "Growing season ahead depends on proper feeding," 7 Mar. 2018
Humans would then drink the water or break it down into hydrogen and oxygen, which could then be used to make breathable air and methane for rocket fuel.

— National Geographic, "Huge Water Reserves Found All Over Mars," 11 Jan. 2018
As hydrocarbon gases sink toward their cores, increasing pressure squeezes out the hydrogen atoms and presses the remaining carbon into diamond, which travels through the planet’s heart as very pricey precipitation.

— gemma tarlach, Discover Magazine, "20 Things You Didn't Know About ... Diamonds," 23 Mar. 2018
Ten days later, also from Paris, the world’s first hydrogen balloon took its first people up, up, and away.

— lauren mccutcheon, Philly.com, "World-famous gas balloonist will lift off at SugarHouse Friday to re-create historic flight," 21 Mar. 2018
The sun currently fuses hydrogen into helium in its interior, a process that began 4.6 billion years ago and will continue for another 3 billion years.

— chicago tribune, chicagotribune.com, "Ask Tom: Is global warming the result of the sun turning brighter as it nears the end of its life?," 14 Mar. 2018
At those pressures, a layer of metallic hydrogen exists, the swirling actions of which generate Jupiter’s magnetic field.

— National Geographic, "New Photo Shows Huge Cyclone Horde on Jupiter," 7 Mar. 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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