O

OASIS	Organization for the Advancement of Structured Information Standards
OGSA	Open Grid Services Architecture
OMG	Object Management Group
OO	object-oriented
OOPSLA	Object-Oriented Programming, Systems, Languages, and Applications
ORB	Object Request Broker
OS	operating system
OS/2	Operating System 2
OS/390	Operating System 390
OSI	Open Systems Interconnection
OU	organizational unit