A domino is a small, thumb-sized rectangular block of wood, bone or other rigid material used as a gaming object. Its face is divided into two parts, each bearing from one to six identifying marks, called pips or spots, the sum of which gives the domino its value. A complete set consists of 28 such pieces, each with a unique number of pips. Dominoes are also known as bones, cards, men or pieces. They are normally twice as long as they are wide, and are often stacked side by side. They are normally held together by a small piece at each end, called a pawn, which is often used to mark its position on the table.
Dominoes are traditionally made of silver lip ocean pearl oyster shell (mother of pearl), ivory, or a dark hardwood such as ebony with contrasting black or white pips. In recent times they have also been made from other natural materials such as stone (e.g., marble or soapstone); metals (e.g., brass or pewter); ceramic clay; and even frosted glass or crystal. Many of the newer domino sets are available in a variety of different materials to appeal to players with a preference for one material over another.
The most popular domino sets are the double-6, double-9, and double-12. Most domino games are designed to be played with the double-6 set. The other sets can be used, but they may require a modification of the rules.
Some domino games are won by the player who reaches a point at which no other player can proceed. This is sometimes called a “chipping out”. The winning player is the one who plays all of his or her remaining dominoes first, although some games require that all partners chip out simultaneously.
The word domino comes from the Latin, dominus, meaning “master of the house”. It later denoted a monastic hood, and then a hooded mask worn at masquerades. It may have also been a reference to the contrast between the black dominoes and the white surplice of the priest.
When a single domino is pushed onto the edge of its stack, it triggers a cascade of movement that spreads outward from it. This is referred to as the domino effect, and is the source of many popular actions and movies.
While you can make a domino fall by pushing on its edge, you can also cause it to fall by just tipping it slightly. This is because the domino has inertia and resists motion until it is pushed past its breaking point. As soon as that happens, it releases its energy in a sudden and rhythmic cascade of action. This is the same principle at work when you play a domino game, and it is the reason that the game can be so addictive. Thousands of dominoes standing right where you left them may seem immobile, but they are just waiting for that tiny nudge that will trigger them all to fall.
