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

MVCC
       MultiVersion Concurrency Control [system] (PostgeSQL, DB)


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

Multi-Version Concurrency Control
MVCC

    (MVCC) An advanced technique for improving
   multi-user database performance.

   The main difference between multiversion and lock models is
   that in MVCC locks acquired for querying (reading) data don't
   conflict with locks acquired for writing data and so reading
   never blocks writing and writing never blocks reading.

   This technique is used in the free software database
   PostgreSQL.

   (1999-06-18)