A domino is a flat thumbsized rectangular block marked on one face with an arrangement of spots, or pips, similar to those on a die. The opposite side is blank or identically patterned. A complete set of dominoes, or domino tiles, contains 28 unique pieces. The most common variant is a double-six set, in which the number of spots on each end ranges from zero to six, although other sets use different combinations of ends. In many games, each player lays a domino that matches the number of pips on the open end of another already-played domino in a line that extends to the edge of the table. This line is called a layout, string or line of play. The first domino played is called a lead. The players continue adding dominoes to the line in turn, matching the pips on their open ends. In the case of a double, each other open end must match it.

A set of dominoes is used to play various positional games in which the first player makes a play by placing a domino, or tile, edge-to-edge against the one to his left. The next player then adds his own tile to the layout, or string, forming a chain. Depending on the game, the next tile added may be required to match the total of the previous play or be required to form some other specified total.

There are also several games in which the value of a domino, or piece, is determined by counting its pips on both sides. This can be done in a number of ways, but often a player will count the dots on the bottom of the domino, and the total of all its pips on both faces is used to determine the value of the piece.

The term domino, and its plural form, dominoes, is derived from the Latin word dominum for “tabletop.” Dominoes are played worldwide and transcend cultural boundaries, serving as a social catalyst and providing an outlet for creative expression. They encourage camaraderie and connection among participants, whether they are gathered in bustling city squares or quiet village homes.

When playing a game of domino, it is best to play on a hard surface such as a wood or concrete table. It is important to be aware of the placement of your tiles, and to try to minimize the amount of time a hand remains exposed to your opponents. In addition, if a domino is accidentally exposed, the player must expose it to all other players immediately and place it back in the boneyard, or stock, where it should remain until the next player draws a hand. If a player draws more than the number of tiles to which he is entitled, this is known as an overdraw and should be corrected immediately by the player to his right. The excess tiles should be removed from his hand without looking at them, and returned to the stock before any other players draw their hands.