Searching for "DSO" in the context of "nvidia" yields "Days Sales Outstanding". Looking at a comprehensive acronym list for "DSO" yields a likely candidate: "Data Source Object" but it is for some sort of Microsoft standard that would seem to be inapplicable to Linux platforms.
From Webopedia:
A dynamic shared object (DSO) is an object file that is intended to be used simultaneously (or shared by) multiple applications while they’re executing. A DSO can be used in place of archive libraries and will minimize overall memory usage because code is shared. Two executables that use the same DSO and that run simultaneously have only one copy of the shared components loaded into memory. [Source: Adapted from SGI]