1. o - Noun
2. o - Adjective
3. o - Preposition
4. o - Interjection
5. o - Particle
7. O - Proper noun
8. o - Symbol
Among the ancients, O was a mark of triple time, from the notion that the ternary, or number 3, is the most perfect of numbers, and properly expressed by a circle, the most perfect figure.
The letter O, or its sound.
Something shaped like the letter O; a circle or oval.
A cipher; zero.
One.
An exclamation used in calling or directly addressing a person or personified object; also, as an emotional or impassioned exclamation expressing pain, grief, surprise, desire, fear, etc.
Source: Webster's dictionarypeople with type O blood are universal donors Source: Internet