- (computing) Open Systems Interconnection An International Standard ISO/IEC 7894:1994(E) subtitled Basic Reference Model. A four part document that contains a formal description of an idealized computer network architecture. The document is also published as ITU-T Recommendation X.200
- Read the ISO Specifications? I can't even lift the ISO Specifications!
- (aviation, travel industry) Other Supplementary Information. A message sent to an airline by an agent, in a standardised format, advising relevant information such as being a VIP, language difficulty, or passport information.
- (software, organisation) Initialism of Open Source Initiative.