(written from a Production point of view)
The term ADR looping is used in the film making industry as an abbreviation for automated dialog replacement or additional dialog recording. It is the technical name for "looping", the process of re-recording dialog following photography. For more information, see dubbing.
As an in-joke for an okudagram made for TNG: "Up The Long Ladder", "ADR looping" was listed as the mission of the SS Seattle, under the command of Wendy Neuss that departed from Earth in 2120. The mission type was rewritten for the remastered version of the episode as a diplomatic mission to SR-47 instead.