Definition of hydrogen Hydrogen

/hajˈdɹʌʤʌn/ - [haydrujun] - hy•dro•gen

We found 11 definitions of hydrogen from 8 different sources.

What does hydrogen mean?

WordNet

Noun Plural: hydrogen
hydrogen - a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe
		H, atomic number 1
		chemical element, element the most favorable environment for a plant or animal; "water is the element of fishes"
		gas the state of matter distinguished from the solid and liquid states by: relatively low density and viscosity; relatively great expansion and contraction with changes in pressure and temperature; the ability to diffuse readily; and the spontaneous tendency to become distributed uniformly throughout any container
		h2o, water a liquid necessary for the life of most animals and plants; "he asked for a drink of water"

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Wiktionary

hydrogen (Noun)
The lightest chemical element symbol H with an atomic number of 1 and atomic weight of 1. 00794.
hydrogen (Noun)
Molecular hydrogen H2, a colourless, odourless and flammable gas at room temperature.
hydrogen (Noun)
An atom of the element.
hydrogen (Noun)
A sample of the element.

Webster DictionaryWebster's Unabridged Dictionary 📘

hydrogen (n.)
A gaseous element, colorless, tasteless, and odorless, the lightest known substance, being fourteen and a half times lighter than air (hence its use in filling balloons), and over eleven thousand times lighter than water. It is very abundant, being an ingredient of water and of many other substances, especially those of animal or vegetable origin. It may by produced in many ways, but is chiefly obtained by the action of acids (as sulphuric) on metals, as zinc, iron, etc. It is very inflammable, and is an ingredient of coal gas and water gas. It is standard of chemical equivalents or combining weights, and also of valence, being the typical monad. Symbol H. Atomic weight 1.

OmegaWiki DictionaryOmegaWiki Dictionary Ω

hydrogen
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 chemicals, in the hydrogenation of fats and oils, and in welding.

Chambers DictionaryChamber's 20th Century Dictionary 📕

hydrogen
hī′dro-jen, n. a gas which in combination with oxygen produces water, an elementary gaseous substance, the lightest of all known substances, and very inflammable.—adjs. Hy′dric, containing hydrogen; Hydrog′enous, containing hydrogen: produced by the action of water, as applied to rocks in opposition to those that are pyrogenous, formed by the action of fire. [A word coined by Cavendish (1766) from Gr. hydōr, water, and genēs, producing.]

Electrical DictionaryThe Standard Electrical Dictionary 💡

hydrogen
An element existing under all except the most extreme artificial conditions of pressure and cold as a gas. It is the lightest of known substances. Atomic weight, 1; molecular weight, 2; equivalent, 1; valency, 1; specific gravity, .0691-.0695. (Dumas & Boussingault.)
It is a dielectric of about the same resistance as air. Its specific inductive capacity at atmospheric pressure is:
.9997 (Baltzman)
.9998 (Ayrton)
Electro-chemical equivalent, .0105 milligram. The above is usually taken as correct. Other values are as follows: .010521 (Kohllrausch)
.010415 (Mascart)
The electro-chemical equivalent of any element is obtained by multiplying its equivalent by the electro-chemical equivalent of hydrogen. The value .0105 has been used throughout this book.

Wikipedia

Hydrogen is a chemical element. It is the simplest atom in the Universe. On a periodic table of the elements, hydrogen is on the top row, usually either on the left, on its own above the transition metals, or Above the Halogens. Its symbol in science is H. Scientists give atoms what they call an atomic number, and the number they have for hydrogen is 1. In its pure form hydrogen is most commonly found on Earth as a gas. Hydrogen is often found in water, but a water molecule is actually made up of one oxygen atom with two hydrogen atoms stuck on one side. Hydrogen is notable in that it is the fuel that powers the Sun and other stars.

Pure hydrogen, though, is normally found in groups of two atoms. Scientists call this diatomic. Hydrogen will have a chemical reaction when mixed with most other elements. It has no color nor smell.

However, hydrogen is very uncommon in the Earth's atmosphere. It is mostly found in water (where it is combined with oxygen) and in all organic compounds and living things. Hydrocarbons, like fossil fuels, are compounds where hydrogen is combined with carbon.

The name "hydrogen" comes from the Greek word for water, 'υδορ (pronounced /HEEW-dor/).

Hydrogen has two different isotopes which are heavier types of the Hydrogen atom, they are called: deuterium and tritium. These other types of Hydrogen are important in nuclear energy.

Hydrogen as fuel (fusion).

Scientists believe atoms are made of protons, neutrons and electrons. From a physics point of view,