The Collaborative International Dictionary of English v.0.48:

personal computer \personal computer\ n.
   1. (Computers) A computer[2] designed for use by one person
      at a time; -- contrasted with shared-time computers such
      as a mainframe, server or minicomputer, which may be
      accessed by multiple users each operating from a different
      input device (in the 1990's, usually a terminal or
      personal computer). A personal computer typically uses a
      microprocessor for its CPU.

   Syn: PC, microcomputer.
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

personal computer
    n 1: a small digital computer based on a microprocessor and
         designed to be used by one person at a time [syn: personal
         computer, PC, microcomputer]

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

personal computer

    (PC) A general-purpose single-user microcomputer
   designed to be operated by one person at a time.

   This term and the concept has been successfully hijacked by
   IBM due to the huge market share of the IBM PC, despite
   its many obvious weaknesses when compared to other equally
   valid claimants to the term, e.g. the Acorn Archimedes,
   Amiga, Atari, Macintosh.

   (1994-11-02)