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

Solaris

    Sun Microsystems, Inc.'s version of the
   Unix operating system.  As well as the core operating
   system, Solaris inludes networking software, the Java Virtual
   Machine, the CDE/Desktop that includes an X11-based
   windowing environment and graphical user interface.

   Sun claim that Solaris is not just an operating system but an
   "operating environment".

   Solaris 1.x was a retroactive (marketing?) name for SunOS
   4.1.x (where x>=1).

   Solaris 2.x (which is the first version most people call
   "Solaris") includes SunOS5.x, which is an SVR4-derived Unix,
   OpenWindows 3.x, and tooltalk.

   (http://sun.com/solaris/).

   (2002-07-15)