Domino is a game played with small rectangular blocks, each bearing from one to six dots or pips. A complete set of dominoes contains 28 tiles. The word also refers to any of the various games played with this system of flat, thumbsized blocks, which can be stacked on end to form long lines or angular patterns. The most popular of these are blocking and scoring games, which involve matching the ends of dominoes or adding them to an existing chain.

When a domino is tipped over it triggers a series of events. Just as a nerve impulse travels from the center of a cell to its ends, so a domino effect can have wide-ranging consequences. The domino effect can be used as a metaphor for describing any sequence of events, both good and bad, that result from one initial action.

A domino game is generally played by two or more players and involves laying a line of dominoes on the table with one end touching an end of another domino in the same row or column. The player who plays a domino in this way is said to “stitch up” the ends of the chain. When one player has completely filled a row or column with dominoes, he wins the game and is awarded points according to the rules of that particular game.

There are a number of different domino games, and the rules for each differ slightly from one game to the next. However, most games depend upon the principle that a domino can be added to an existing chain by matching its end with one of the free ends of an already played tile. Some of these games allow for the purchase of dominoes from the stock (see Byeing below) which are then added to a player’s hand.

In some games a player’s seating arrangement at the table is determined by lot. In other games, the first player to draw a tile that he is able to play seats himself at the table, either on the left of the dealer or opposite him. If a player draws more dominoes for his hand than he is permitted to take, he is said to have overdrawn, and any excess tiles are returned to the stock and reshuffled before that player’s turn begins.

The word domino, as well as the game, has an interesting history. Both the word and the game are believed to have evolved from a much earlier sense of the word, which denoted a hooded cloak worn with a mask at carnival time or at a masquerade. In the English language, it is possible that this sense was borrowed from French, where domino originally meant a cape worn by a priest over his surplice. It is suggested that the connection between this garment and the playing piece was a symbol of a priest’s black domino contrasting with his white surplice. In any event, the word and the game appeared in France shortly after 1750.