A 20 sided die used in many games in the "Dungeons & Dragons" series of tabletop role-playing board games.
Carl: Say Falacorn, let's break out the d20 and set us up a game of *gasp* DUNGEONS AND DRAGONS.
Joe: Indeed Yeldor, but I call dungeon master!
*slap fight ensues*
by Wesley Durrance July 22, 2005
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A twenty sided die, or a system which has been used to base games off of. Also damages the Dungeon Master's walls after rolling low many consecutive times.
Player: Sonofabitch! Another 1?! How dare you betray me?!

*Throws d20 in a random direction as hard as he can*

Dungeon Master: Goddamnit Joe! That's the fourth time you've done that! I'm sure as fuck not paying if there's any damage!
by Kerik July 12, 2006
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1: A 20 sided die. 2: A gaming system devloped to play Dungeons and Dragons and other table-top RPGs.
1: Roll a d20.
2: We could play Star Wars d20 or Modern d20.
by Ryan March 2, 2004
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The first open Liscense gaming system.

Yet another gaming system that held great potential but was ruined by over priced books , Unthought out rules, and market whoring.
Have you see the new d20 version of Cuthlullu
by Telos March 2, 2004
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A 20 sided die to keep track of your life total in Magic, the Gathering.
Where is my d20, I need to keep track of my life total.
by McDutch July 17, 2008
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A 20 sided die that dm’s use to infuriate their players.
Dm: roll arcana
Leon: are you fucking kidding me
Jim: did it roll low again?
Emma: just get better a better d20
Leon: fuck you
by Car’s son March 23, 2021
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