Domino is a small flat rectangular block of a material such as wood or bone that is used as a gaming object. Dominoes, also known as bones, cards, men, or pieces, are normally twice as long as they are wide and feature a line in the middle that visually divides them into two squares. Each square features a value, from six pips down to blank or none. The number of pips is called the rank or weight of the tile, and a heavier tile has more pips than a lighter one.

There are many different types of domino games, but most of them fall into four categories: bidding games, blocking games, scoring games, and layout or round games. The most common domino sets are double six and double nine, although larger sets do exist.

In the game of domino, players lay tiles out in a line and then place a single tile on top of that, either in front of or behind it. The first player to complete the row by placing a tile in the correct spot makes a play, and then each subsequent player must follow that pattern. The rules vary from game to game, but most of them are straightforward and easy to learn.

One of the most interesting things about domino is that a single piece can tip a whole line of them over with just a little nudge. It is like the domino effect in physics: a chain reaction that starts with just one little push and grows exponentially until it reaches the critical mass of all the other elements.

The word domino is derived from the Latin for “falling together” or “linking up.” It can be traced back to an earlier sense of the word that refers to a garment worn at carnival season or during a masquerade. This is probably the connection that brings to mind images of people assembling and stacking large lines of dominoes for display.

Domino is a popular children’s toy, and it can be used to teach counting and addition. It is often played with two or more people, and it can be made into a very complicated game by adding additional rules. Some of the most difficult games are those that involve a lot of strategy and planning.

In some games, players may choose to buy tiles from the stock, which is a group of unplayed dominoes. Usually the player with the highest double in his hand is allowed to make the first play, but rules can vary.

Some players choose to count the pips on the ends of the dominoes as they are played, and this is called the count. This is done by comparing the total of the pips in each side to that of the matching half of another adjacent tile, or a domino with both its sides open. This method of counting is called the domino count, and it is a valuable tool in calculating scores.