Domino is a small tile that represents the roll of two dice. It has a line down its center to visually divide it into two squares, each of which is marked with an arrangement of dots, called pips, that vary from domino (the most common) to blank (or none). The pips identify the value of one end of the tile, and the total number of pips on either side determines its rank or weight. Dominoes are often referred to as bones, cards, men, or tiles.

A domino is most commonly used for positional games, in which each player takes turns laying a domino edge-to-edge against another in such a way that the adjacent faces match or form some other specified total (e.g., five to six). In these games the number of pips on each tile identifies its rank. The more pips a domino has, the higher its rank.

The word “domino” is actually derived from the Italian noun domino, which in turn comes from the French verb démembre, meaning to delineate or mark with a marker. The earliest mention of domino is from 1750, and it appears to have entered English shortly thereafter. In its earlier sense, the word domino meant a hooded cloak worn with a mask at carnival season or during a masquerade.

Dominoes are usually played on a table, with each player starting out with a set of dominoes and then taking turns placing them. The first player to have all their dominoes in a line is the winner. However, there are many variations on the basic rules that change the outcome of a game and make it more difficult to win.

For example, some people prefer to make all the blank sides of a domino wild and assign any value to them that they choose. Others prefer to only play tiles that have a particular value, such as a domino with 3 or 1 pips on both sides. In either case, a player can’t go again until someone else successfully places a domino with a matching value.

The physics of dominoes is fascinating, and many players enjoy creating intricate layouts that will tumble when the first domino is struck. A 20-year-old professional domino artist, Lily Hevesh, has amassed a huge following on YouTube for her impressive displays, and she works on large-scale projects for movies, TV shows, and events. Some of her larger setups take several nail-biting minutes to fall, but Hevesh says that one physical phenomenon is key to her success: gravity.

She has worked on projects involving 300,000 dominoes and helped set a Guinness record for the most dominoes in a circular arrangement. She says that gravity plays a major role in her projects, as the force of the falling dominoes causes them to fall into each other and cause further dominoes to fall in a chain reaction.