waldo /wol'doh/ [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.