H2O

 Dictionary entry overview: What does H2O mean? 

• H2O (noun)
  The noun H2O has 1 sense:

1. 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

  Familiarity information: H2O used as a noun is very rare.

 Dictionary entry details 

• H2O (noun)

Sense 1

Meaning:

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

Classified under:

Nouns denoting substances

Synonyms:

H2O; water

Hypernyms ("H2O" is a kind of...):

binary compound (chemical compound composed of only two elements)

liquid (fluid matter having no fixed shape but a fixed volume)

Meronyms (substance of "H2O"):

atomic number 8; O; oxygen (a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust)

atomic number 1; H; 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)

Hyponyms (each of the following is a kind of "H2O"):

ground water; spring water; well water (underground water that is held in the soil and in pervious rocks)

water of crystallisation; water of crystallization; water of hydration (the water present in hydrated compounds)

bilge; bilge water (water accumulated in the bilge of a ship)

soft water (water that is not hard (does not contain mineral salts that interfere with the formation of lather with soap))

slush (partially melted snow)

fresh water; freshwater (water that is not salty)

brine; saltwater; seawater (water containing salts)

meltwater (melted snow or ice)

limewater (solution of calcium hydroxide in water used as an antacid)

hard water (water that contains mineral salts (as calcium and magnesium ions) that limit the formation of lather with soap)

holy water (water that has been blessed by a priest for use in symbolic purification)

distilled water (water that has been purified by distillation)

dishwater (water in which dishes and cooking utensils are washed)

bath water (water used for a bath)

tap water (water directly from the spigot)

Holonyms ("H2O" is a substance of...):

tear; teardrop (a drop of the clear salty saline solution secreted by the lacrimal glands)

ice; water ice (water frozen in the solid state)

diamond dust; frost mist; frost snow; ice crystal; ice needle; poudrin; snow mist (small crystals of ice)

flake; snowflake (a crystal of snow)

body of water; water (the part of the earth's surface covered with water (such as a river or lake or ocean))

perspiration; sudor; sweat (salty fluid secreted by sweat glands)

 Context examples 

There’s evidence that the Moon has water (H2O) and hydroxyl (OH), a more reactive relative of H2O.

(Meteoroid Strikes Eject Precious Water From Moon, NASA)

OH in the atmosphere also forms when ultraviolet sunlight reaches the lower atmosphere and reacts with water vapor (H2O) and ozone (O3) to form two OH molecules.

(Greenhouse Gas ‘Detergent’ Recycles Itself in Atmosphere, NASA)

C3 contains a thioester group that is spontaneously hydrolyzed at a slow rate to create C3(H2O).

(Alternative Complement Pathway, NCI Thesaurus/BIOCARTA)

Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n.

(Carbohydrate, NLM, Medical Subject Headings)

Examples of compounds include water (H2O), which is made from the elements hydrogen and oxygen, and table salt (NaCl), which is made from the elements sodium and chloride.

(Compound, NCI Dictionary)

Deubiquitinating Enzymes are hydrolases that catalyze cleavage of ubiquitinated substrates with addition of H2O at the point of cleavage.

(Deubiquitinating Enzyme, NCI Thesaurus)

But using special instruments, scientists can detect two types: regular water, H2O, and heavy water, HDO, which has an extra neutrally-charged particle called a neutron inside one of the hydrogen atoms.

(Comet Provides New Clues to Origins of Earth's Oceans, NASA)

Enzymes (EC class 3) cleaving substrates with addition of H2O at the point of cleavage; e.g., esterases, phosphatases, nucleases, peptidases.

(Hydrolase, NCI Thesaurus)

The research also suggests that any H2O present on the Moon isn’t loosely attached to the surface.

(On Second Thought, the Moon's Water May Be Widespread and Immobile, NASA)

A class of macronutrients constructed from carbon, oxygen and hydrogen that have the general formula Cn(H2O)m.

(Dietary Carbohydrate, NCI Thesaurus/CRCH)