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

child process

    A process created by another process (the
   parent process).  Each process may create many child
   processes but will have only one parent process, except for
   the very first process which has no parent.  The first
   process, called init in Unix, is started by the kernel
   at boot time and never terminates.  A child process inherits
   most of its attributes, such as open files, from its parent.
   In fact in Unix, a child process is created (using fork) as
   a copy of the parent.  The chid process can then overlay
   itself with a different program (using exec) as required.

   (1997-11-22)