The Jargon File (version 4.4.7, 29 Dec 2003):

wetware
 /wet'weir/, n.

    [prob.: from the novels of Rudy Rucker]

    1. The human nervous system, as opposed to computer hardware or software. ?
    Wetware has 7 plus or minus 2 temporary registers.?

    2. Human beings (programmers, operators, administrators) attached to a
    computer system, as opposed to the system's hardware or software. See 
    liveware, meatware.


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

wetware

    /wet'weir/ (Probably from the novels of Rudy Rucker,
   or maybe Stanislav Lem) The human nervous system, as opposed
   to electronic computer hardware or software.  "Wetware has
   7 plus or minus 2 temporary registers."  Also, human beings
   (programmers, operators, administrators) attached to a
   computer system, as opposed to the system's hardware or
   software.

   See liveware, meatware.

   [True origin?  Dates?]

   [Jargon File]

   (1996-08-19)