From Wikipedia, the free encyclopedia.
XO may refer to:
- Executive officer (military)
- XO grade of cognac
- Crystal oscillator
- Tic-tac-toe (a game)
- Eastern Orthodoxy (Christianity), from the Greek: Xristianos Orthodoksos (Χριστιανός Ορθόδοξος)
- Crossover track
- XO Communications, a telecom company
- Kisses (X) and hugs (O) (may be repeated), a common postscript to a love letter
