WordNet (r) 3.0 (2006):

bedrock
    n 1: solid unweathered rock lying beneath surface deposits of
         soil
    2: principles from which other truths can be derived; "first you
       must learn the fundamentals"; "let's get down to basics"
       [syn: fundamentals, basics, fundamental principle,
       basic principle, bedrock]

The Free On-line Dictionary of Computing (19 January 2023):

Bedrock

   A C++ class library for Macintosh user interface
   portability.