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

System V
System 5
Unix System V

   1. The other major versions of the Unix operating system
   apart from BSD.  Developed by AT&T.  Later versions of
   Unix such as SunOS combined the best features of System V
   and BSD Unix.

   (1994-10-31)

   [Differences?]

   2. A supplier of Unix open systems for Intel x86
   processors.  They supply products from SCO and Solaris and
   offer general support for Unix, TCP/IP, and Internet.
   They serve and create third-party WWW pages and provide
   on-line support for commercial and non-commercial applications.

   (http://systemv.com/).

   See also System V Interface Definition.

   (1994-12-12)