Library / English Dictionary

HYDROGEN

Pronunciation (US):

(GB):

 I. (noun) 

Sense 1

Meaning:

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

Synonyms:

atomic number 1; H; hydrogen

Classified under:

Nouns denoting substances

Hypernyms ("hydrogen" is a kind of...):

chemical element; element (any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter)

gas (a fluid in the gaseous state having neither independent shape nor volume and being able to expand indefinitely)

Hyponyms (each of the following is a kind of "hydrogen"):

tritium (a radioactive isotope of hydrogen; atoms of tritium have three times the mass of ordinary hydrogen atoms)

Holonyms ("hydrogen" is a substance of...):

H2O; water (binary compound that occurs at room temperature as a clear colorless odorless tasteless liquid; freezes into ice below 0 degrees centigrade and boils above 100 degrees centigrade; widely used as a solvent)

Derivation:

hydrogenate (combine or treat with or expose to hydrogen; add hydrogen to the molecule of (an unsaturated organic compound))

Credits

 Context examples: 

A small molecule made of one carbon and three hydrogen atoms.

(Methyl group, NCI Dictionary)

The oxidized substrate is regarded as a hydrogen donor.

(Oxidoreductase Gene, NCI Thesaurus)

For the model, they put grains of “naphthalene and biphenyl — two toxic, carbon and hydrogen bearing compounds believed to exist on Titan’s surface — into a small cylinder.”

('Electric Sands' Cover Titan, VOA News)

For example, the molecular mass of water, which has two atoms of hydrogen and one atom of oxygen, is 18 (i.e., 2 + 16).

(Molecular mass, NCI Dictionary)

For example, the molecular weight of water, which has two atoms of hydrogen and one atom of oxygen, is 18 (i.e., 2 + 16).

(Molecular weight, NCI Dictionary)

This species is nonmotile, non-spore forming, indole positive, produces hydrogen sulfide, does not reduce nitrate, hydrolyzes esculin and starch, does not ferment trehalose, melezitose or arabinose, and is penicillin resistant.

(Bacteroides fragilis, NCI Thesaurus)

They can replace the hydrogen of an acid and form bases with hydroxyl radicals.

(Metal, NCI Thesaurus)

This species is nonmotile, non-spore forming, catalase negative, resistant to penicillin, hydrolyzes esculin, indole negative and does not produce hydrogen sulfide.

(Bacteroides caccae, NCI Thesaurus)

This species is spore forming, catalase positive, oxidase negative, indole negative, does not produce hydrogen sulfide, reduces nitrate, and hydrolyzes starch and esculin.

(Bacillus polymyxa, NCI Thesaurus)

A process in which the hydrogen ion concentration of a solution is decreased, resulting in an increase in alkalinity.

(Alkalinization, NCI Thesaurus)