What does hydrogen mean?
Hydrogen is the chemical element with the symbol H and atomic number 1. It is a colorless, odorless, highly flammable gas and the most abundant element in the universe, although most of it exists in stars and compounds such as water rather than as free hydrogen gas on Earth. The word combines Greek roots meaning “water” and “produce,” reflecting the traditional practice of generating it from an acid and a metal. In scientific contexts, hydrogen is used to describe the element, atoms of the element, or the gas itself. In modern energy discussions, it is also called a clean fuel when produced by splitting water using renewable electricity, although its overall environmental benefits depend on how it is made and transported. Hydrogen bonding is a separate and important scientific concept describing an electrostatic attraction between a hydrogen atom and certain atoms in nearby molecules.
nounA colorless, odorless, flammable gaseous chemical element that is the most abundant element in the universe and combines with almost every other element. In chemistry, hydrogen has the symbol H and atomic number 1.
- The chemical element with symbol H and atomic number 1, a colorless and highly reactive gas that combines with many other elements.
- Hydrogen in its gaseous state, especially when used as an energy source or fuel.
"Hydrogen is increasingly being used as a clean source of energy for powering vehicles and generating electricity."
"The experiment demonstrated how hydrogen is produced from water."
"Green hydrogen is being developed to replace fossil fuels in industries that are difficult to electrify."
Usually used when referring to individual atoms or molecules of hydrogen; the plural is uncommon in general prose.
"The two hydrogens are bonded to one oxygen atom in each water molecule."
Hydrogen powers the stars and is the lightest element, yet a single hydrogen atom contains one of the universe's most common particles: a proton.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of hydrogen
Hydrogen was coined in the early 19th century from Greek hydōr, meaning “water,” and gennan, meaning “to produce.” The name reflects the then-established fact that hydrogen could be generated from an acid and a metal, and it was known as a component of water. Its many English relatives include hydro-, hydrate, hydrocarbon, and hydrous, all of which reflect the older association of hydrogen with water or its chemical combinations.
Related word forms
How hydrogen is actually used
In general writing, hydrogen usually refers to the chemical element or to hydrogen gas. In energy and environmental discussions, terms such as green hydrogen, blue hydrogen, and gray hydrogen refer to hydrogen produced using different energy sources and processes.