Domino is a game played by two or more players with small rectangular blocks of wood, bone, ivory, silver lip ocean pearl oyster shell (mother-of-pearl), or other materials, with a number showing on one face and blank or identically patterned on the other. Each domino has a pips (or spots) arrangement similar to that of a die, except that the number showing on a domino is always a multiple of six.

Dominoes can be arranged to form straight, curved, or other patterns and are typically used in conjunction with other game pieces such as dice or pegs. Regardless of the exact pattern, every domino must touch the end of another to play. This allows a chain reaction to begin and continue. Eventually, the entire set of dominoes comes crashing down in a spectacular display.

While most domino sets have the same basic rules, there are many variations in how they are used. Some games require that hands be drawn before a player plays; other games allow for byeing (taking tiles from the stock without drawing). Moreover, some games use a different scoring method; counting only the pips on the ends of a double in place of the total number of pips in a domino.

Although the word domino has a rather modern origin, it seems that its name is closely linked to another, earlier sense of the word, namely a long hooded cloak worn together with a mask during carnival season or at a masquerade. This robe may have inspired the design of the domino, with its ebony blacks and white surplices.

As a piece of wood, domino is relatively heavy and therefore has a lot of potential energy stored in its position. Standing a domino upright, however, against the pull of gravity converts much of this energy into kinetic energy, which causes the domino to fall. In the same way, writing a novel requires careful planning but is ultimately all about reaction and how one action triggers a chain of events that leads to an unexpected conclusion.

In addition to the standard polymer sets, dominoes can also be made of bone, silver lip ocean pearl oyster shell (mother-of-pearl), ivory, or other natural materials such as marble, granite, soapstone, or other woods; metals such as brass or pewter; ceramic clay; or even frosted glass. These are often more expensive than polymer sets but offer a unique, high-end appearance and feel to them.

For some players, it is a matter of style to make their dominoes look as spectacular as possible. A famous example of this is the work of Lily Hevesh, a professional domino artist who has created stunning setups for movies, TV shows, and other events. She tests out the various sections of her installations and films them in slow motion so she can adjust the dominoes until they are in the perfect positions. This attention to detail also helps her to create a smooth flow of action in her videos, which have attracted more than 2 million YouTube subscribers.