The Free On-line Dictionary of Computing (19 January 2023):

waldo

   /wol'doh/ [Robert A. Heinlein's story "Waldo"] 1. A mechanical
   agent, such as a gripper arm, controlled by a human limb.
   When these were developed for the nuclear industry in the
   mid-1940s they were named after the invention described by
   Heinlein in the story, which he wrote in 1942.  Now known by
   the more generic term "telefactoring", this technology is of
   intense interest to NASA for tasks like space station
   maintenance.

   2. At Harvard (particularly by Tom Cheatham and students), this is
   used instead of foobar as a metasyntactic variable and general
   nonsense word.

   [Jargon File]

   (2015-03-22)


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

waldo
 /wol'doh/, n.

    [From Robert A. Heinlein's story Waldo]

    1. A mechanical agent, such as a gripper arm, controlled by a human limb.
    When these were developed for the nuclear industry in the mid-1940s they
    were named after the invention described by Heinlein in the story, which he
    wrote in 1942. Now known by the more generic term telefactoring, this
    technology is of intense interest to NASA for tasks like space station
    maintenance.

    2. At Harvard (particularly by Tom Cheatham and students), this is used
    instead of foobar as a metasyntactic variable and general nonsense word.
    See foo, bar, foobar, quux.