Role-playing game terms are words used in a specific sense (terms) in the context of role-playing games. This includes both terms used within RPGs to describe in-game concepts and terms used to describe RPGs. Role-playing games also have specialized slang jargon associated with them.
Critical: A type of result associated with a strong outcome, especially a critical hit or critical failure (fumble). Often related to unlikely die results, as a natural 1 or 20, doubles, and so forth.
DC: Difficulty Class, a number result needed to save from an effect or spell.
Fumble: An unforced error when attempting a difficult task. Also known as a Botch.
Game master: The person who runs a role-playing game and arbitrates how actions are resolved and narrated. Abbreviated GM. In many games, specialized terms are used, as such Dungeon Master for someone running Dungeons & Dragons.
Gamemaster's screen: a foldout cardboard-made accessory, used by the game master to hide from the players' eyes any information related to the adventure they are playing. Abbreviated GM screen (or DM screen when talking about Dungeons & Dragons gamemaster's screens).
Initiative: The determination of who goes first and in what order declared actions are carried out.
Metagaming: Using out-of-character knowledge to solve in-character problems, or to explain in-character behaviour.
Modifier: A number added to or subtracted from a die roll.
Natural (roll): The number actually on a die, such as a natural 1 or a natural 20, indicating the die's face shows a 1 or a 20, as opposed to the number rolled plus modifiers.