I. ˈō noun
( plural o's or os ˈōz)
Usage: often capitalized, often attributive
Date: before 12th century
1.
a. : the 15th letter of the English alphabet
b. : a graphic representation of this letter
c. : a speech counterpart of orthographic o
2. : a graphic device for reproducing the letter o
3. : one designated o especially as the 15th in order or class
4. : something shaped like the letter O ; especially : zero
II. abbreviation
1. ocean
2. ohm
3. old
4. order
5. over