- ON
- Ontario (Regional » Canada Provinces)* Order Now (Miscellaneous » Food)* Order Now (Business » International Business)* Order Now (Business » General)* Open Network (Computing » Networking)* Optic neuritis (Medical » Physiology)* Oxidation Number (Academic & Science » Chemistry)* Orden Nuevo (International » Spanish)* Operational Navigation (Governmental » Military)* Operational Navigation (Governmental » NASA)* Operational Navigation (Governmental » Transportation)* The Operators For Not (Computing » General)
Abbreviations dictionary. 2012.