Domino is a type of game played with small rectangular wooden or plastic blocks, each marked on one side with an arrangement of dots or “pips” similar to those used on dice. The other side of each domino is blank or identically patterned. The pips distinguish one domino from another, but they do not affect the outcome of a game; instead, players simply match them with other tiles to advance their play. Each time a domino is played, it creates a chain that can grow into an elaborate pattern. The earliest known reference to the word and game dates from 1750, but their origin is unclear. The word is related to the French term domino, which earlier denoted a long hooded cloak worn together with a mask at carnival season or at a masquerade.
The rules of different domino games vary considerably. However, in general, the first player begins by drawing a hand of tiles that correspond to the number required by the specific game. He then places these tiles in front of him so that the pips are hidden from the other players. After a hand is drawn, the player may draw additional tiles to add to his hand, depending on the rules of the particular game being played.
Each domino has two matching ends that must touch when a tile is played on them. Depending on the game, these end pairs may be oriented in any of three ways: a line touching at both sides (a cross-ways or snake-line) or perpendicular to each other (a square touching only at one side). Dominoes can also be played diagonally.
When a double is played on an open end, the open side of the second domino becomes the new end of the line of play and the count continues in this manner. Occasionally, an open end may not be a “spinner”; for example, the 5-5 domino may only be played on two sides. In such cases, a count may still be made when the total of the end of the line of play reaches a certain amount, but only after all other possible options are exhausted.
Once the players have drawn their hands, the next step is to determine who will make the first play of the game. Several methods are used to do this, including drawing lots or choosing the heaviest tile. The player who chooses to begin the game with a double may be referred to as the setter, the downer, or the lead.
Once the order of play is established, each player takes turns playing a domino. If a player does not have any tiles that can match the one being played, she must wait until someone else plays a tile that matches. Generally, a person who does not make a play does not score that turn. In some cases, though, the player who makes the last play of a game may be awarded points based on the number of ends of the line that remains.