A flat, thumb-sized rectangular block bearing from one to six pips (or dots) and usually painted or inlaid with black or white: 28 such dominoes form a complete set. A set of dominoes is used to play a variety of games. Blocking and scoring games such as bergen, muggins, matador, and Mexican train are among the most familiar; dominoes also help children learn number recognition and math skills. Dominoes can be laid in a number of ways: in lines and angular patterns, on grids that make pictures when they fall, in 3D structures like towers and pyramids.

The game of domino was probably first developed in the mid-18th Century in Italy and France. It arrived in Britain in the late 18th Century from France (possibly via French prisoners of war) and quickly became popular in inns and taverns. In the early 19th Century, European dominoes were produced in many materials, including bone, silver lip ocean pearl oyster shell (mother of pearl), ivory, and ebony with contrasting black or white pips inlaid or painted onto each side. More recently, domino sets have been made from plastics such as polymer clay and resin. The dominoes made from natural materials tend to feel heavier and more substantial in the hand than those made from polymer.

For the most part, dominoes are used for playing positional games in which a player takes turns placing one domino edge to edge against another so that the exposed ends match (e.g., a 1 touching a 1 or a 2 touching a 2) or form some specified total. Dominoes are also used for making domino puzzles such as those in which the player is given a pattern and asked to place tiles based on their arithmetic properties (e.g., a line of five and a tile halves).

In the past several years, dominoes have become popular as decorations for parties and other special occasions. They are often used in conjunction with other items, such as balloons and flowers, to create centerpieces. Many people also use them to decorate their homes, particularly in areas where a fireplace is present.

Dominoes are sometimes used in art, such as sculpture and collage. In the latter, the pieces are often painted or glued together in a mosaic-like arrangement to create a picture. Many people also use them to make their own domino art: they can choose from a variety of shapes and colors for the individual dominoes, and then arrange them on a canvas or other surface in a way that makes sense to them.

In stories, dominoes are used to build scenes. It is important that these scenes advance the story and don’t get too long, or they may overwhelm the reader. At the same time, they must not be too short or they will not have any impact at key points in the plot. For this reason, writers often write scene dominoes that are relatively insignificant on their own, but when placed in the right sequence they have a dramatic effect.