hydrogen

noun

hy·​dro·​gen ˈhī-drə-jən 

-dər-

: 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

—often used before another noun

hydrogen gas

hydrogen atoms

a hydrogen vehicle

the hydrogen industry

see Chemical Elements Table compare deuterium, tritium

hydrogenous

hī-ˈdrä-jə-nəs 

adjective

Examples of hydrogen in a Sentence

Recent Examples on the Web

Follow him on LinkedIn, Bluesky and Threads for news on electric and autonomous vehicles, high-speed rail, battery and hydrogen technology, or contact him by email [e-mail] Join The Conversation Comments 0 One Community. —Alan Ohnsman, Forbes, 24 Feb. 2025

By tracking the movements of hydrogen, iron and sodium specifically, the team were able to trace out the winds in Tylos' shallow, deep and mid atmospheric layers, respectively. —Matt Robison, Newsweek, 18 Feb. 2025

Chlorophyll is necessary for photosynthesis, the process that takes carbon and oxygen from carbon dioxide and hydrogen from water to make carbohydrate, a plant’s energy source. —Joshua Siskin, Orange County Register, 14 Feb. 2025

That's because even hydrogen, by far the universe's most abundant element, emits only a faint glow that our astronomical instruments have struggled to observe between stars and galaxies. —Robert Lea, Space.com, 12 Feb. 2025

Word History

Etymology

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

First Known Use

1788, in the meaning defined above

Phrases Containing hydrogen

• heavy hydrogen
• hydrogen bomb
• hydrogen bond
• hydrogen bromide
• hydrogen chloride
• hydrogen cyanide
• hydrogen fluoride
• hydrogen iodide
• hydrogen ion
• hydrogen peroxide
• hydrogen sulfide

Rhymes for hydrogen

• dihydrogen

Kids Definition

hydrogen

noun

hy·​dro·​gen ˈhī-drə-jən 

: a chemical element that is the simplest and lightest of all chemical elements and is normally found alone as a colorless odorless highly flammable gas having two atoms per molecule see element

hydrogenous

hī-ˈdräj-ə-nəs 

adjective

Etymology

from French hydrogène "hydrogen," from hydr- "water" and -gène "producer"; so called because when hydrogen gas burns, it combines with oxygen to produce water

Medical Definition

hydrogen

noun

hy·​dro·​gen ˈhī-drə-jən 

: 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

hydrogenous

hī-ˈdräj-ə-nəs 

adjective