![[P]](http://cache.lexico.com/g/d/premium_mh.gif){kind=small}
hy·dro·gen 
Audio Help [hahy-druh-juhn] Pronunciation Key
Audio Help [hahy-druh-juhn] Pronunciation Key –noun
| a colorless, odorless, flammable gas that combines chemically with oxygen to form water: the lightest of the known elements. Symbol: H; atomic weight: 1.00797; atomic number: 1; density: 0.0899 g/l at 0°C and 760 mm pressure. |
| Dictionary.com Unabridged (v 1.1) Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006. |
Hydrogen
To learn more about Hydrogen visit Britannica.com
| © 2008 Encyclopædia Britannica, Inc. |
| hy·dro·gen
Audio Help (hī'drə-jən) Pronunciation Key
n. Symbol H A colorless, highly flammable gaseous element, the lightest of all gases and the most abundant element in the universe, used in the production of synthetic ammonia and methanol, in petroleum refining, in the hydrogenation of organic materials, as a reducing atmosphere, in oxyhydrogen torches, and in rocket fuels. Atomic number 1; atomic weight 1.00794; melting point -259.14°C; boiling point -252.8°C; density at 0°C 0.08987 gram per liter; valence 1. See Table at element. [French hydrogène : Greek hudro-, hydro- + French -gène, -gen.] hy·drog'e·nous (-drōj'ə-nəs) adj. |
| The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2006 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved. |
hydrogen
1791, from Fr. hydrogène, coined 1787 by G. de Morveau from Gk. hydr-, stem of hydros "water" + Fr. -gène "producing." So called because it forms water when exposed to oxygen. Hydrogen bomb first recorded 1947; shortened form H-bomb is from 1950.
| Online Etymology Dictionary, © 2001 Douglas Harper |
| hydrogen | |
noun | |
| 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 |
| WordNet® 3.0, © 2006 by Princeton University. |
hydrogen [ˈhaidrədʒən] noun
an element, the lightest gas, which burns and which, when combined with oxygen, produces water
See also: hydrogen bomb
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Kernerman English Multilingual Dictionary, © 2000-2006 K Dictionaries Ltd. |
| hydrogen
Audio Help (hī'drə-jən) Pronunciation Key
Symbol H The lightest and most abundant element in the universe, normally consisting of one proton and one electron. It occurs in water in combination with oxygen, in most organic compounds, and in small amounts in the atmosphere as a gaseous mixture of its three isotopes (protium, deuterium, and tritium) in the colorless, odorless compound H2. Hydrogen atoms are relatively electropositive and form hydrogen bonds with electronegative atoms. 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 and oils, and to refine petroleum. The development of physical theories of electron orbitals in hydrogen was important in the development of quantum mechanics. Atomic number 1; atomic weight 1.00794; melting point -259.14°C; boiling point -252.8°C; density at 0°C 0.08987 gram per liter; valence 1. See Periodic Table. See Note at oxygen. |
| The American Heritage® Science Dictionary Copyright © 2002 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved. |
hydrogen
The lightest chemical element; its symbol is H. Hydrogen normally consists of a single electron in orbit around a nucleus made up of a single proton. It is usually found as a gas and has several uses as a fuel.
Note: Hydrogen atoms are combined to form helium atoms in fusion reactions in stars and in hydrogen bombs, which release huge amounts of energy. Hydrogen also burns rapidly, producing water as it combines with oxygen (see H8O and oxidation).
Note: For a time, hydrogen was frequently used to fill blimps and dirigibles because of its extremely low weight. In 1937, however, the hydrogen in the dirigible Hindenburg caught fire, and many of the passengers and crew were killed. Since that time, helium has been widely preferred to hydrogen for use in airships; it is not as buoyant (see buoyancy) or cheap as hydrogen, but, being an inert gas, it does not burn.
Note: Because there is so much hydrogen in stars, it is by far the most abundant element in the universe.
[Chapter:] Physical Sciences and Mathematics
| The American Heritage® New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved. |
Hydrogen
Hy"dric\, a. [From Hydrogen.] (Chem.) Pertaining to, or containing, hydrogen; as, hydric oxide. Hydric dioxide. (Chem.) See Hydrogen dioxide, under Hydrogen. Hydric oxide (Chem.), water. Hydric sulphate (Chem.), hydrogen sulphate or sulphuric acid.| Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc. |
View results from: Dictionary | Thesaurus | Encyclopedia | All Reference | the Web
Share This: 
Perform a new search, or try your search for "Hydrogen" at:
- Amazon.com - Shop for books, music and more
- Reference.com - Encyclopedia Search
- Reference.com - Web Search powered by Google
- Thesaurus.com - Search for synonyms and antonyms
