1. (noun)
oxygen, O, atomic number 8
- 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 Synonyms: type O, oxygen, group O, atomic number 8
2. (noun)
O, o
- the 15th letter of the Roman alphabet Synonyms: type O, oxygen, group O, atomic number 8
3. (noun)
O, type O, group O
- the blood group whose red cells carry neither the A nor B antigens Synonyms: type O, oxygen, group O, atomic number 8