Domino, pronounced doh-MINO, is a game of skill and chance that involves arranging and then knocking down a row of dominoes. It is played with a rectangular set of dominoes, each with an identical pattern on one side and a different pattern, typically an arrangement of dots called pips, on the other. Each domino has a number on its pips or blank squares, but some are also blank (indicated by the letter “0”). The term dominoes may be applied to the entire game, or to a specific type of layout, such as a curved line, a grid that forms pictures when fallen, or a 3D structure such as a tower or pyramid.
The name comes from the Latin domina, meaning “flip,” which is the action of flipping a tile over to reveal its other face. The earliest dominoes were made of ivory or bone and carved with an arrangement of pips, but more durable woods such as ebony soon became popular, along with clay and metal. A domino’s pips are usually black, although white or silver ones are sometimes used as well.
In the 1800s, European domino games gained popularity in France and Austria. The game spread from there to Germany and southern Europe. The word domino appears in English from the early 1870s, though its exact origin is unknown.
Most commercially available dominoes are of the double-six and double-nine variety, which come in 28 pieces each. These sets represent all of the possible combinations of ends on two thrown dice, including the blank sides, or “pips.” Other, larger, sets exist and are commonly used for long, multi-player domino games.
Like playing cards, which originated in the 13th century, dominoes are arranged into suits. Each suit contains all of the numbers from one to nine, plus four dominoes that are blank or have no pips at all. The number of pips on a domino and the arrangement of those pips determines which of the two suits it belongs to.
When a domino is standing upright, it stores energy as potential energy. As it falls, that energy is converted into kinetic energy, causing the next domino in line to fall as well. As the chain reaction continues, each domino picks up more and more speed and kinetic energy until it eventually stops.
The same principle applies to real-life events. For example, a simple infection can lead to a cascade of more severe infections in hospital patients. These are often referred to as nosocomial infections, and they can be caused by many things, from improper cleaning of instruments to a medical professional simply forgetting to wash his or her hands. In fact, a domino effect can even be seen in the way in which an idea or event may be spread, such as by viral advertising or political propaganda.