Definition of "o"

The fifteenth letter of the English alphabet, called o and written in the Latin script.  examples

(astronomy) used as an abbreviation of omicron in star names.  examples

The ordinal number fifteenth, derived from this letter of the English alphabet, called o and written in the Latin script.  examples

The name of the Latin-script letter O/o.  examples

A zero (used in reading out numbers).  examples

(nonstandard) alternative form of O (vocative particle)  quotations

Alternative form of oh  examples

(IRC, acronym of) Operator  examples

(acronym of) Object, see SVO  examples

Over  examples

Alternative form of of  examples