Domino (or dominoes) is a game played with a set of small rectangular wood or plastic blocks, each marked by two groups of dots resembling those on dice. A domino is normally twice as long as it is wide, with the numbers on the ends varying between zero and six (in the most common variant, called double-six).
When a single domino is placed on a surface, it starts a chain reaction that results in the falling of the rest of the set. The first player to place all of his or her tiles wins the hand. The game can also be played as a cooperative activity, in which the players share responsibility for placing and stacking all of the tiles.
The game is generally governed by a set of rules, some of which depend on the specific tile layout and the number of players. The most important rules are the following:
Most domino sets have a central line that divides the tile visually into two squares, each of which is labeled with a value (numbers) in the form of dots or letters, depending on the variant being used. Most dominoes have a value from zero up to six, while some are blank or have a minus sign. The values on each end of the domino indicate its rank or weight, which is a function of the sum of the numbers on both sides.
In general, the higher the rank or weight of a domino, the more difficult it is to knock over. The first player to play his or her tiles begins by placing one domino at a time on the edge of a table or other flat surface, such as a floor, usually with its face toward the tabletop. The next player must then place a matching domino on the other end of the row, aligned with the first tile and touching it in some way (either directly or diagonally). This continues in turn until all of the tiles are played.
Dominoes are commonly made of ivory, silver-lipped mother of pearl oyster shell, bone or a dark hardwood such as ebony. More recently, a variety of other natural and synthetic materials have been used for the faces and bases of dominoes. For example, some sets are made of ceramic clay, marble, granite, or soapstone; carved bone, ivory or slate; metals such as brass and pewter; or other types of wood, including mahogany.
The word “domino” may be derived from the Latin word for “fall”, in reference to the chain reaction of dominoes. However, it could also be an allusion to its shape, as it resembles a traditional Latin letter (D).
The use of the word in English dates back to at least 1750, when it was in common usage for both the game and its playing pieces. Earlier, the term denoted a long hooded cloak worn together with a mask at a carnival or masquerade, and may have evoked the image of the priest’s black domino contrasting with his white surplice.