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

TSO
       Telecommunications Service Order


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

TSO
       Time Sharing Option


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

Time Sharing Option
TSO

    (TSO) System software from IBM that
   provides time-sharing on an IBM mainframe running in an
   MVS environment.

   (2003-08-15)