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

The proprietary set of conditions created by the lasers breaks the bonds between iron and oxygen in the ore without needing carbon or expensive green hydrogen to act like a bouncer that carries the unwanted oxygen away. —Andrew Rosenblum, Popular Science, 26 Dec. 2024

While there may not be enough heavy elements to produce lots of rocky worlds, gas giants such as Jupiter and Saturn are mostly hydrogen and helium, which is plentiful everywhere. —Keith Cooper, Space.com, 20 Dec. 2024

Usually, these protostars gather enough mass to generate the pressures and temperatures in the core to fuse hydrogen to helium, which is the nuclear process that defines what a main sequence star is. —Robert Lea, Space.com, 24 Dec. 2024

This process involves adding hydrogen to unsaturated fats—which are liquid at room temperature, such as vegetable oil—to make trans-fat, which is shelf-stable and solid and room temperature. —Hatty Willmoth, Newsweek, 24 Dec. 2024

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

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