|o or O (əʊ)|
|—n , pl o's, O's, Os|
|1.||the 15th letter and fourth vowel of the modern English alphabet|
|2.||any of several speech sounds represented by this letter, in English as in code, pot, cow, move, or form|
|3.||another name for nought|
|O or O|
|2.||See universal donor a human blood type of the ABO group|
|3.||logic A E Compare I a particular negative categorial proposition, such as some men are not married: often symbolized as SoP|
|4.||slang (Austral) offence|
|[(for sense 3) from Latin (neg)o I deny]|
|1.||a variant spelling of oh|
|2.||an exclamation introducing an invocation, entreaty, wish, etc: O God!; O for the wings of a dove!|
|forming informal and slang variants and abbreviations, esp of nouns: wino; lie doggo; Jacko|
|[probably special use of |
|Compare -i- used to connect elements in a compound word: chromosome; filmography|
|[from Greek, stem vowel of many nouns and adjectives in combination]|
The Greek letter omicron. Entries beginning with this character are alphabetized under omicron.
The symbol for the element oxygen.
ortho- (often italic)
The symbol for oxygen.
|oxygen (ŏk'sĭ-jən) Pronunciation Key
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 -218.4°C; boiling point -183.0°C; gas density at 0°C 1.429 grams per liter; valence 2. See Periodic Table.
Our Living Language : 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.