Domino is a family of tile-based games in which players place dominoes edge to edge across the table. Each domino has an identity-bearing side that bears a pattern of dots, like the spots on a die, and a blank or identically patterned opposite side. The first player to play a domino with a matching side (usually a number) sets the direction in which other tiles are played. Typically, subsequent plays must be made either lengthwise or crosswise of the previous tile.

The most popular domino games fit into four categories: bidding games, blocking games, scoring games, and round games. Some games, such as poker or trick-taking, have elements of several different categories. Most dominoes have a set of instructions printed on them that give the rules for how the game is played, including how to set up the dominoes and what moves can be made.

One of the most fascinating aspects of domino is that a single small action can start a long sequence of events, much like a domino effect. A famous example occurred in the 1960s, when American President Dwight Eisenhower cited the analogy of falling dominoes in response to a question about America’s decision to assist South Vietnam in its struggle against Communist insurgents. The idiom has since come to refer to any situation in which one event may cause other events to follow, often with unexpected and significant results.

As a hobby, many people enjoy setting up and then playing dominoes, either in straight lines or curved ones, on flat surfaces such as the floor. Others, such as domino artist Nick Vermette, are more ambitious, building impressive sculptural structures with the tiny tiles. Many of his works are made in a garage, where he uses tools such as a drill press, radial arm saw, scroll saw, belt sander, and welder to create intricate curved shapes, grids that form pictures, stacked walls, and 3D pyramids. He has also built dominoes for movies, TV shows, and events, including an album launch for singer Katy Perry.

The term domino is also used in more technical contexts, such as the software product called IBM Domino that allows organizations to run Java applications on any platform and on any cloud. This allows companies to scale their infrastructure and improve productivity without the complexity of maintaining and upgrading multiple platforms or worrying about data security and compliance.

For a fun and educational activity, set up a line of dominoes, and then lightly touch each one with your finger. Watch what happens, and then experiment with a few more times, moving your finger a little farther forward each time, to see how far you can get the dominoes to fall. You can even try this at home using a small, plastic domino set. You can find these sets in most toy stores. A more advanced version is to use an actual domino set with a larger and heavier set of pieces. Then, try to make them fall in an unusual way, such as by putting a piece down that is not required, or by pushing the pieces apart with varying amounts of force.