A traditional die is a cube with each of its six faces showing a different number of dots (known as pips). When rolled, the die comes to rest showing on its upper surface a random number from one to six, each value being equally likely.
Check out this YouTube video by Numberphile on Fair Dice:
Dice have been used since before recorded history and it is uncertain where they originated. The oldest known dice are estimated to be from between 2800–2500 BC and were excavated at the Burnt City in south-eastern Iran.
Other historical references:
There is an Egyptian racing game known as Senet was played before 3000 BC.
There are several biblical references to "casting lots", as in Psalm 22.
The Romans were passionate gamblers who enjoyed dicing, which was known as aleam ludere ("to play at dice").
Twenty-sided dice date back to the 2nd century AD and from Ptolemaic Egypt as early as the 2nd century BC.
For more information:
Dice – from Wikipedia, the free encyclopedia