Definition

One. [Obs.] Chaucer. "Alle thre but o God." Piers Plowman.

Other Definitions

This word also has 2 other definitions:

O (interjection)

An exclamation used in calling or directly addressing a person or personified object; also, as an emotional or impassioned exclamation expressing pain...

O (noun)

1. O, the fifteenth letter of the English alphabet, derives its form, value, and name from the Greek O, through the Latin. The letter came into the Gr...