I don’t think DM is a trademark, but if you have other information feel free to provide it. Looking through older discussion forums on this topic, the only semi-definitive answer I’ve found is in this 2021 thread where somebody referred to a now-defunct US gov’t trademark search link, where they said they found a lot of "DM"s registered but none related to D&D. I’m inclined to believe it was a working link at that time and they weren’t just making shit up.
Personally I use the term DM because I’ve mostly played D&D, so to me it’s more natural.
My primary source at the time of posting was a sentence in the Wikipedia[1] but I have added the link to the trademark[2] that was provided by Kichae and rephrased my text now.
Thank you for reminding me that I should always properly check my sources and provide all information.
I don’t think DM is a trademark, but if you have other information feel free to provide it. Looking through older discussion forums on this topic, the only semi-definitive answer I’ve found is in this 2021 thread where somebody referred to a now-defunct US gov’t trademark search link, where they said they found a lot of "DM"s registered but none related to D&D. I’m inclined to believe it was a working link at that time and they weren’t just making shit up.
Personally I use the term DM because I’ve mostly played D&D, so to me it’s more natural.
“DM” is not a trademarked term, because it’s a pair of letters. “Dungeon Master” is absolutely a trademarked term, though, and has been since the TSR days.
Thank you for this information, I have added it to my original comment.
My primary source at the time of posting was a sentence in the Wikipedia[1] but I have added the link to the trademark[2] that was provided by Kichae and rephrased my text now.
Thank you for reminding me that I should always properly check my sources and provide all information.
[1] https://en.wikipedia.org/w/index.php?title=Dungeon_Master&oldid=1185015796 [2] https://trademarks.justia.com/742/64/dungeon-74264094.html