DMing

DMing is a relatively new word coming from the role playing game culture, which began to be used in the mid-1970s. "DMing" consists of the combination of the acronym of "DM" and the suffix "ing". "DM" is an acronym for "Dungeon Master", which is the title given to the person that referees or "tells" the story in a role-playing game, such a LARP game of "Dungeons & Dragons". Thus, "DMing" essentially means 'Dungeon Mastering-ing', i.e. doing the task of a "Dungeon Master".

Historically speaking, "DMing" started the tradition of gaming companies of "officially" providing a naming convention by giving a official sounding title to the referee of their role-playing game. It appears that TSR is the first game producing company to do so for their Dungeons & Dragons role playing game.

Plus, "DMing" is also analogous to the task as a GM or Game Master, which in this case "GM" refers to someone that is the senior expert or the person acting as the Referee or Rules Interpretor of a complicated recreational game. Typically, GM is reserved for complicated tactics and strategy games, such as any type of role-playing game or a tactic & strategy game such as Starfleet Battles board game.

RPG gamers frequently interchange the usage of DM with GM and DMing with GMing