Domino is a small oblong piece of wood or other material bearing an arrangement of spots on one side and blank or identically patterned on the other. It is used to play a variety of games where the players try to place pieces end to end in order to form a line, with each piece matching the value of an adjacent domino.
Dominoes, also called bones, cards, men or pieces, were first recorded as a game in the mid-18th century in Italy and France. They were introduced into England by French prisoners toward the end of that same period. Most commonly, dominoes are arranged in a line end to end so that the adjacent faces match either in number (e.g., 5 to 5) or in some specified total such as 21.
When a domino is tipped or knocked over, it has the potential energy to push over all of its neighbors in a cascade. However, only some of this energy is transferred to the next domino; most remains in the previous domino as it becomes a part of the falling structure (see Converting Energy to Kinetic Energy). When all of the dominoes have fallen, the remaining potential energy becomes kinetic energy and the sequence stops.
A domino set consists of 28 tiles, traditionally in the form of squares, each with a numbered end that is a match for a number on either a face or a pips (or dots) column. Each end of a domino is distinguished by its color or surface markings (see the Image gallery). A domino set also includes a stock of shuffled tiles, referred to as the boneyard, from which each player draws seven tiles to begin playing.
In addition to the standard blocking and scoring games, dominoes can be used to play a variety of other games that involve skill or chance. For example, some players place dominoes on the edge of a table and then move them by hand to create patterns. Another popular domino game involves a dice-like die, which is rolled to determine the value of a placed domino.
In the past, some domino sets were made from natural materials such as silver lip ocean pearl oyster shell (mother of pearl or MOP), ivory, and a dark hardwood such as ebony. These sets have a more novel appearance and may be heavier to hold. Other types of dominoes have been made from ceramic clay; metals such as brass or pewter; frosted glass or crystal; and the polymer acetate.