oxygen

[ ok-si-juhn ]

noun

, Chemistry.

1. a colorless, odorless, gaseous element constituting about one-fifth of the volume of the atmosphere and present in a combined state in nature. It is the supporter of combustion in air and was the standard of atomic, combining, and molecular weights until 1961, when carbon 12 became the new standard. : O; : 15.9994; : 8; density: 1.4290 grams/liter at 0°C and 760 millimeter pressure.

oxygen

/ ɒkˈsɪdʒɪnəs; ˌɒksɪˈdʒɛnɪk; ˈɒksɪdʒən /

noun

1. 1. a colourless odourless highly reactive gaseous element: the most abundant element in the earth's crust (49.2 per cent). It is essential for aerobic respiration and almost all combustion and is widely used in industry. Symbol: O; atomic no: 8; atomic wt: 15.9994; valency: 2; density: 1.429 kg/m³; melting pt: –218.79°C; boiling pt: –182.97°C
   2. ( as modifier )

      an oxygen mask

oxygen

/ ŏk′sĭ-jən /

1. A nonmetallic element that exists in its free form as a colorless, odorless gas and makes up about 21 percent of the Earth's atmosphere. It is the most abundant element in the Earth's crust and occurs in many compounds, including water, carbon dioxide, and iron ore. Oxygen combines with most elements, is required for combustion, and is essential for life in most organisms. Atomic number 8; atomic weight 15.9994; melting point −218.8°C; boiling point −182.9°C; gas density at 0°C 1.429 grams per liter; valence 2.
2. See Periodic Table

oxygen

1. An element , normally a gas , that makes up about one-fifth of the atmosphere of the Earth . Oxygen is usually found as a molecule made up of two atoms . Its symbol is O.

Notes

Oxygen is a waste product of green plants and photosynthesis .

When we breathe in oxygen, it is carried by the hemoglobin in our blood throughout the body, where it is used to generate energy by oxidation . ( See respiration .)

Derived Forms

• oxygenic, adjective

Other Words From

• ox·y·gen·ic [ok-si-, jen, -ik], ox·yg·e·nous [ok-, sij, -, uh, -n, uh, s], adjective
• ox·y·gen·ic·i·ty [ok-si-j, uh, -, nis, -i-tee], noun

Word History and Origins

Origin of oxygen¹

First recorded in 1780–90; from French oxygène, equivalent to oxy- + -gène; oxy- ¹, -gen

Word History

In 1786, the French chemist Antoine Lavoisier coined a term for the element oxygen ( oxygène in French). He used Greek words for the coinage: oxy– means “sharp,” and –gen means “producing.” Oxygen was called the “sharp-producing” element because it was thought to be essential for making acids. Lavoisier also coined the name of the element hydrogen, the “water-producing” element, in 1788. Soon after, in 1791, another French chemist, J. A. Chaptal, introduced the word nitrogen , the “niter-producing” element, referring to its discovery from an analysis of nitric acid.

Example Sentences

While this phenomenon has been studied in light molecules such as ammonia, oxygen, hydrochloric acid or simple carbon compounds, it has hardly been studied in molecules with heavier atoms.

From Science Daily

The solution contains molecules called ligands that are made up of carbon and oxygen.

From Science Daily

One, Amin Khan, said from behind an oxygen mask that he joined the march knowing that, "either I will bring back Imran Khan or I will be shot".

From BBC

The cabin altitude checklist includes "immediate use of oxygen masks".

From BBC

"I have lived the best and worst part of my career with the Ballon d'Or and then injury, but it gives me oxygen to come back again in a good way," he said.

From BBC