V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

OSA
       Object System Adaptor (SOM)


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

OSA
       Office Systems Administrator (OA)


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

OSA
       Open Scripting Architecture (Apple, OS/2)


The Free On-line Dictionary of Computing (30 December 2018):

OSA

   1. Open Scripting Architecture.

   2. Open System Architecture.