from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A nonmetallic element constituting 21 percent of the atmosphere by volume that occurs as a diatomic gas, O2, and in many compounds such as water and silica, and in iron ore. It combines with most elements, is essential for plant and animal respiration, and is required for nearly all combustion. Ozone, O3, is an allotrope of this element. Atomic number 8; atomic weight 15.9994; melting point −218.79°C; boiling point −182.9°C; gas density at 0°C 1.429 grams per liter; valence 2. cross-reference: Periodic Table.

from The Century Dictionary.

  • noun Chemical symbol, O; atomic weight, 16. An element discovered by Priestley in 1774, who called it dephlogisticated air.
  • noun A manufacturers' name for bleaching-powder.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Chem.) A colorless, tasteless, odorless, gaseous element of atomic number 8, occurring in the free state in the atmosphere, of which it forms about 23 per cent by weight and about 21 per cent by volume, being slightly heavier than nitrogen. Symbol O. Atomic weight 15.9994.
  • noun Manufacturing name Chlorine used in bleaching.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun A chemical element (symbol O) with an atomic number of 8 and relative atomic mass of 15.9994.
  • noun Molecular oxygen (O2), a colorless, odorless gas at room temperature.
  • noun medicine A mixture of oxygen and other gases, administered to a patient to help him or her to breathe.
  • noun countable An atom of this element.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun 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


from The American Heritage® Dictionary of the English Language, 4th Edition

[French oxygène : Greek oxus, sharp, acid; see ak- in Indo-European roots + French -gène, -gen.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

Borrowed from French oxygène (originally in the form principe oxygène, a variant of principe oxigine ‘acidifying principle’, suggested by Lavoisier), from Ancient Greek ὀξύς (oxus, "sharp") + γένος (genos, "birth"), referring to oxygen's role in the formation of acids.


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  • He thought that experiments proved all acids to be compounds of the element oxygen; and for many years after Lavoisier, the alchemical expression _the principle of acidity_ was superseded by the word _oxygen_.

    The Story of Alchemy and the Beginnings of Chemistry

  • So, too, they claim that there are two distinct processes carried on by the leaves of plants, -- namely, respiration and digestion: that the first is analogous to the same process in animals; and that by it oxygen is absorbed from, and carbonic acid returned to the atmosphere, though to a limited degree: and that digestion consists in _the decomposition of carbonic acid by the green tissues of the leaves under the stimulus of the light, the fixation of solid carbon, and the evolution of pure oxygen_.

    The Atlantic Monthly, Volume 08, No. 47, September, 1861

  • a compound containing hydrogen and oxygen in the proportion of 1 part by weight of hydrogen to 7.94 parts by weight of oxygen_.

    An Elementary Study of Chemistry

  • This oxygen comes from the orbiter main oxygen supply while the suit is connected and from a "bail out bottle" after the crewman leaves the seat.

    Columbia Report Issued - NASA Watch

  • By the time the rescuers get to the main collapse area, their oxygen is almost at it limits.

    52 listed as dead in Russian mine blast; 38 missing

  • I do like steampunk - which is what I call my oxygen concentrator, "Turn on the Steampunk!"

    Goth girl tries something "quiet" and "peaceful" to aid recovery (think bones!)

  • He does not know anything about what we call oxygen; but it is astonishing how very easy it would be to turn his language into the equivalent of modern chemical theory.


  • Plants can form what he calls oxygen (O) roots and water/nutrient (W/N) roots.

    17: Above-ground (urban) gardens

  • He does not know anything about what we call oxygen; but it is astonishing how very easy it would be to turn his language into the equivalent of modern chemical theory.

    Lectures and Essays

  • The oxygen is fed through a connector at the left thigh, entering the helmet at the base of the neck ring.

    Kuriositas: The 10 Coolest Space Suit Designs


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    December 16, 2007