The question What's the name of cardboard wall DMs use to hide their part of table? has a fairly clearcut answer–"X Master's Screen," where X is "Game" or "Dungeon" depending on the speaker, the game being played, and possibly other regional and/or cultural factors.
The Wikipedia article on the subject linked from the other question gives a quick history of TSR products called "Dungeon Masters/Master's Screen"s, from the late '70s onwards. The first such made by TSR was released with, or shortly after, the first Advanced Dungeons and Dragons (often retconned as "D&D 1e") books. I started playing tabletop RPGs around that time, and I remember the product having, on the DM side, a straightforward reprinting of a number of useful tables selected from the Player's Handbook and the Dungeon Master's Guide but mostly from the latter. I also clearly remember the art on the "outside" facing the players of the edition of the screen I saw most often–the fat, grinning demonic idol also pictured on the cover of the first few printings of the AD&D Player's Handbook:
I'm calling attention to the art here just because it may jog others' memories. I'm interested in knowing whether TSR coined the term "DM's Screen," which then (at least in my gaming circles, for what it's worth) became a universal term for that accessory, regardless of what game system was actually being played. Or were there already similar products from other publishers on the market (or were people making homebrew versions) and TSR just used the prevailing jargon?
Best Answer
The Judge's Shield (1977) predates the Dungeon Master's Screen by about two years, give or take some months. (That the Judge's Guild got to this first is not surprising, as Gygax infamously told them that nothing but rules would sell, and the Judge's Guild was fated to prove him wrong.) So the term “shield” was established before the term “screen”, and still has minority currency today.
The Referee Screen (1979) for Traveller has the same vintage as the DM's Screen and is the only other data point before the 80s begin. It's unclear which was published first that year and therefore which one coined the term “screen”, but together with their two popular games — D&D and Traveller — they certainly had a large enough combined audience to establish the term “screen” in common usage over the the term “shield”, and likely TSR's audience alone would have been enough to establish the term as definitive. (Judge's Guild material, although designed for use with D&D and acclaimed at the time, was not “official” and that would have prevented a lot of play groups that didn't stray from TSR-branded material from being exposed to the alternate term.)
The history isn't very interesting, unfortunately. The only reason we have more than one word for it is because “shield” enjoyed first-to-market advantage in establishing mindshare enough to not be completely destroyed by the TSR juggernaut's adoption and promulgation of the term “screen.”
The “GM Screen” variation, as noted in the other question's answer, is merely a variation of the term that follows the separate trend of the hobby adopting “game master” as a non-trademarked, non-D&D-specific term, whether out of a hobbyist's need for precision or a publisher' need to avoid legal trouble. The term “GM screen” therefore doesn't have much of an interesting history of its own. You can see “GM screens” in a few early items: