Domino is a game in which players arrange tiles on the table in long lines. Each tile has a specific pattern of spots, or “pips,” on one side and blank or identically patterned on the other. The number of pips on each end determines its value, which may range from zero to six. Some of the pips may also be marked with letters, which correspond to suits. The first domino to fall, or “go out,” triggers the rest of the line to topple. The result is a chain reaction, which can create complex patterns and add a surprising amount of energy to the game.
The word “domino” also refers to a process or event that triggers a series of increasingly greater consequences, often with catastrophic results. The phrase “domino effect” is used in popular culture to refer to a situation in which an initial action leads to a chain reaction that ultimately has a much larger impact than was initially expected.
One of the best examples of the domino effect is the collapse of the Twin Towers on September 11, 2001, which triggered a chain reaction that led to other terrorist attacks in the United States and around the world. The phrase also has been applied to economic and financial events, such as the foreclosure crisis and the 2008 stock market crash.
Although the term was not used in English until the early 19th century, the game of domino has been around for hundreds of years. It surfaced in Italy, southern Germany and France before a fad spread through Europe. In the mid-18th century, it became a popular pastime in England. The name for the game, however, does not appear until 1771 in the Dictionnaire de Trevoux.
Dominoes are normally twice as long as they are wide, and the ends are shaped to fit together. They are arranged in sets of different sizes, called suits, and each suit has a particular color and a certain pattern of pips. Each domino features a line down the middle to divide it visually into two squares, or ends. Each end of a domino has a value, based on the arrangement of pips.
Most domino games are played by positioning tiles in a layout so that adjacent ends match either identically (one’s touching one’s) or form a specified total (for example, five to seven). Each tile is then stacked vertically on top of the next, with the pips facing up. Occasionally, additional tiles are placed cross-ways in the layout, straddling an existing double or forming a new end with an open space for another tile.
If the end of a domino is closed by another tile, it is not considered to have a value and is not eligible to be played. When this occurs, the second player must choose a tile from the boneyard until they can find one with an open end that matches a previous domino. Then they can continue playing the dominoes until they win or lose all their tiles.