Definition: 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.
Definition: The letter O, or its sound.
Definition: Something shaped like the letter O; a circle or oval.
Definition: A cipher; zero.
Definition: 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.