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

MCA
       Micro Channel Architecture (IBM, PS/2)


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

MCA
       Mission Critical Applications


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

MCA
       Model Centric Architecture (Skynamics)


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

Micro Channel Architecture
MCA

    (MCA) IBM's proprietary 32-bit bus, used in
   high-end PS/2 personal computers.  Micro Channel is
   designed for multiprocessing.  It eliminates potential
   conflicts that arise when installing new peripheral devices.
   MCA is *not* compatible with either EISA or XT bus
   architecture so older cards cannot be used with it.

   As with the ROM BIOS in the first IBM PCs, figuring out
   the Micro Channel's secrets has been an arduous task of
   reverse engineering ever since the PS/2 line was announced.
   Consequently, the MCA has never become as wide spread as the
   competing EISA standard.

   (1996-08-16)