Not a citation, either, but I believe the original
RUNCOM came from CTSS (
https://multicians.org/shell.html)
Yes, the CTSS command "runcom" arranged for commands stored in a file
to be run in the background. Such a file (which could contain at most
six commands) became known as "a runcom".
The term "script" did not emerge until Unix. I vaguely recall that Lee
McMahon coined the usage, but would welcome more reliable info about
its origin.
Doug