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

hole model

    A model of semiconductor behaviour in which
   donors contribute a positive charge equal in magnitude to the
   charge of an electron, and acceptors contribute space for such
   a charge within the crystal lattice.

   The hole model was proposed well before electrons were discovered
   and described.  Much of electronics, especially at the
   engineering level, continues to consider current as flowing from
   positive to negative.

   (1995-10-05)