Four-sided dice are often used in role-playing game

Role-playing game

A role-playing game is a game in which players assume the roles of characters in a fictional setting. Players take responsibility for acting out these roles within a narrative, either through literal acting, or through a process of structured decision-making or character development...

s, such as Dungeons & Dragons

Dungeons & Dragons

Dungeons & Dragons is a fantasy role-playing game originally designed by Gary Gygax and Dave Arneson, and first published in 1974 by Tactical Studies Rules, Inc. . The game has been published by Wizards of the Coast since 1997...

, to get small numbers for things such as damage or character statistic increases. Each die

Dice

A die is a small throwable object with multiple resting positions, used for generating random numbers...

 is a tetrahedron

Tetrahedron

In geometry, a tetrahedron is a polyhedron composed of four triangular faces, three of which meet at each vertex. A regular tetrahedron is one in which the four triangles are regular, or "equilateral", and is one of the Platonic solids...

 with 4 equilateral

Equilateral

In geometry, an equilateral polygon is a polygon which has all sides of the same length.For instance, an equilateral triangle is a triangle of equal edge lengths...

 triangle

Triangle

A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....

-shaped faces. This type of die does not roll well and is thus usually thrown into the air or shaken in a dice box instead. Some games like daldøs

Daldøs

Daldøs [dal'døs] is a running-fight board game only known from a few coastal locations in Scandinavia, where its history can be traced back to around 1800. The game is notable for its unusual four-sided rolling-pin style dice . In Denmark it is known as daldøs in Northern and Western Jutland , and...

 use a four sided rolling-pin that rolls much better.

Tetrahedral dice are peculiar in that there is no topmost face when a die comes to rest. There are several common ways of indicating the value rolled. On some tetrahedral dice, three numbers are shown on each face. The number rolled is indicated by the number shown upright at all three visible faces - either near the midpoints of the sides around the base, or near the angles around the apex. Another configuration places only one number on each face, and the rolled number is shown on the downward face.

The ancient Royal Game of Ur

Royal Game of Ur

The Royal Game of Ur, also known as the Game of Twenty Squares, refers to two game boards found in the Royal Tombs of Ur in Iraq by Sir Leonard Woolley in the 1920s. The two boards date from the First Dynasty of Ur, before 2600 BC, thus making the Royal Game of Ur probably the oldest set of board...

 also uses 4-sided dice made out of rock. It is believed, however, that they had only individual dots on each side (1, 2, 3, 4), instead of the 3-way formation used in modern-day DnD-style dice.

Because of their size and shape and the tendency of dice to fall on the floor, with a point facing up and underfoot, gamers frequently refer to four-sided dice as caltrop

Caltrop

A caltrop is an antipersonnel weapon made up of two or more sharp nails or spines arranged in such a manner that one of them always points upward from a stable base...

s.