What is O?

O definition and meaning on Dictionary terms:
noun, plural O’s or Os; o’s or os or oes.
the fifteenth letter of the English alphabet, a vowel.
any spoken sound represented by the letter O or o, as in box, note, short, or love.
something having the shape of an O.
a written or printed representation of the letter O or o.
a device, as a printer’s type, for reproducing the letter O or o.


reference: https://www.dictionary.com/browse/o