A twenty-sided die
Alright, so to attack, you roll a d20 and add your STR modifier to the result. Then, we'll figure out if you hit ...
|D&D||Dungeons and Dragons|
|LGS||Local game store|
When your Dungeon Master (DM) tells you to roll a d20, they want you to roll a twenty-sided die. This unusual icosahedron is associated primarily with Dungeons & Dragons (DnD), but is also used in a variety of other tabletop and online games.
While archaeologists have unearthed d20s that date back to the 2nd century and feature ancient characters, the current incarnation's 20 faces each show a number from 1 to 20. In D&D and other games, players sometimes roll a d20 to determine whether they succeeded or failed at a task, such as attacking an enemy or telling a convincing lie.
Typically, if a player rolls a 1 on a d20, their attempt counts as a critical failure (meaning it automatically fails). Likewise, if a player rolls a 20 on a d20, their attempt usually counts as a critical success (meaning it automatically succeeds).
The d20 is only one of many specialized dice that players use to play D&D, other RPGs, and tabletop board games. For example, you may also see gamers use d12s, d10s, d8s, and d4s, as well as the d6s used by more traditional games. However, because it holds so much power over a story's outcome, the d20 holds a special place in D&D players' hearts.