Hydrogen is a chemical element; it has the symbol H and atomic number 1. It is the lightest and most abundant chemical element in the universe, constituting about 75% of all normal matter.

Feb 27, 2026 · The earliest known chemical property of hydrogen is that it burns with oxygen to form water; indeed, the name hydrogen is derived from Greek words meaning ‘maker of water.’

The meaning of HYDROGEN is 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 …

HYDROGEN definition: a colorless, odorless, flammable gas that combines chemically with oxygen to form water: the lightest of the known elements. H; 1.00797; 1; density: 0.0899 grams/liter at 0°C and …

HYDROGEN definition: 1. a chemical element that is the lightest gas, has no colour, taste, or smell, and combines with…. Learn more.

In the sun and other stars, the conversion of hydrogen into helium by nuclear fusion produces heat and light. Hydrogen is used to make rocket fuel, synthetic ammonia, and methanol, to hydrogenate fats …

Hydrogen can be produced, or separated, from a variety of sources—including water, fossil fuels, or biomass—and used as a source of energy or fuel. Hydrogen has the highest energy content of any …

a flammable colourless gas that is the lightest and most abundant element in the universe. It occurs mainly in water and in most organic compounds and is used in the production of ammonia and other …

Definition of hydrogen noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

Hydrogen is the most abundant element in the universe, making up about 75% of all elemental matter. Hydrogen has three naturally occurring isotopes: protium (1H), deuterium (2H), and tritium (3H), with …