Dice are polyhedral random determinators.
Standard dice are six-sided, marked with one to six dots. Dice have been used since ancient times.
Polyhedral dice, introduced with Dungeons & Dragons have anywhere from four to thirty sides. They have been in use in a number of hobbies since the mid-20th century, and have existed at various times and places throughout history.
Typically, they are numbered rather than marked with pips. The regular polyhedrons, known as the platonic solids, are the d4 (tetrahedron), the d6 (hexahedron), the d8 (octahedron), the d12 (dodecahedron), and d20 (icosahedron). The d10 has a regular form, but the faces are not regular polygons, and likewise the d30.
Rollers, spinners, and dice with non-polygonal faces have been devised, both for the standard number of faces as well as nonstandard numbers of faces.
The conventional way of indicating a die is DX or dX, where X is the number of sides. For instance, d8 refers to an eight-sided die. A leading number indicates how many dice to roll. For instance, 3d6 means roll three six-sided dice.
The probability curveEdit
A single die roll results in what is called a flat distribution. That is, each result has an equal result of occuring. Rolling 2d6, however, (that is, rolling two ordinary six-sided dice together), results in a different distribution. There is only one result out of thirty-six possiblities that is a 2. There is also only one 12. However, there are six different ways of adding up to 7, making 7 the mode, or most common result. Increasing numbers of dice have a stronger central tendency and less very high or very low numbers. Larger dice have more very high or very low numbers.