o   (TTS Sound)

The noun o has 3 senses

• 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)


• O, o -- (the 15th letter of the Roman alphabet)


• O, type O, group O -- (the blood group whose red cells carry neither the A nor B antigens; "people with type O blood are universal donors")