Old School Revival, or Old School Renaissance. A movement to reinvigorate the style of roleplaying from the 1970s and 1980s, often with a focus on older editions of D&D.
The Old School Essentials role playing game.
Sometimes debuffing (like 'hold person' spells), and sometimes employing game mechanics that diminish a game element in an unfair or arbitrary way.
Magic Points (or Mana Points) that are used in some games to determine the magic force of a game element.
The environment in which an adventure or campaign takes place. The "snowglobe" of a Story Crucible. Often populated by active agents.
Using out of character (OOC) information for In-Character (IC) decisions.
An adventure plotline and decision that feeds back into the setting to spark new plotlines and gameplay. Can be open or closed. See loopy planning. See also: https://www.roleplayingtips.com/npc...ns-and-immortals-3/#16-loopy-session-planning
A plot hole that can disrupt a game session, sidetrack an adventure, and even derail a campaign. See also: https://www.roleplayingtips.com/rptn/rpt002-time-bomb-solution/
A combat tactic where some participants break away from the fray and try to lure their enemies to follow, using the 'divide and conquer' tactic.
In-Game mindset or "role playing". See IC.