In-Character PC talk/mindset. See IG.
Hit Points, often used in D&D-style games to determine the life force of game elements such as PCs, NPCs, structures, and objects.
A style of play where the characters freely explore hex-map terrain, encountering whatever locations, creatures and events that are located in the hex they enter. See also https://thealexandrian.net/wordpress/15156/roleplaying-games/game-structures-part-6-hexcrawls
The 'Gamism, Narrativism, Simulationism' theory. The original inspiration for the Wizard of Adventure GM Triangle. See also: https://en.wikipedia.org/wiki/GNS_theory
Game Master - also called DM (Dungeon Master), storyguide, referee, and other names.
In-game details that do not impact game mechanics. The opposite of crunch.
A standalone gameplay situation with a beginning and an end that should have conflict and stakes.
Damage Per Round. A metric for estimating the challenge level of combat encounters.
Game details that are mechanics or affect mechanics or dice rolls. The opposite of fluff.
Campaign Logger, a GM organization application created by @JochenL and @JohnnFour to help GMs stay on top of campaign details.