OCN is a three letter abbreviation that stands for:OCLC Control Number, a bibliographic record identifier In Oncology nursing, an Oncology Certified Nurse Opaskwayak Cree Nation Open College Network, a UK education organisation today known as NOCN Open Computer Network, a major Internet Service Provider in Japan Orange County Newschannel, a defunct cable television news network targeted toward Orange County, California Original Camera Negative, the film stock used in a movie camera Orion Cinema Network, a South Korean television network Orthodox Christian Network Originally called number, in telephony, the phone number of the originally called party, regardless of call redirection; look inside a Signalling System No. 7 (SS7) ISDN User Part (IUP) initial address message (IAM) for this optional parameter Operating Company Number, in telephony, a code used in various iconectiv telephony products, a major subset of which equate to Company Codes assigned by the National Exchange Carrier Association (NECA) to telecommunications carriers. Order confirmation number, a method for recording purchase orders in many Enterprise resource planning (ERP) systems