*The slang term “one trick pony” is used to refer to something which can only be used for one very specific application. The term is also used to describe people; for example, a chef who can only produce one really good dish might be known as a one trick pony. The term is generally used in a disparaging way, since it suggests a lack of flexibility and an inability to work outside very specific parameters. Most people try to avoid creating or becoming a one trick pony for this very reason.

The term probably originates from the “dog and pony shows” of the early American era. A dog and pony show was a small circus with a limited number of animals and performers, and often the performances were simple or lackluster. Trick ponies and horses have a long history of being used in circus performance, but a horse that only does one trick wouldn't be very interesting or impressive to watch.

Some industries are particularly prone to turning out one trick ponies. In software development, a very limited program can be a serious liability, for example, since while it may attract attention at first, users will abandon it if it does not develop into a more rounded whole. Some devices in the computer industry could also be considered one trick ponies, making them much less attractive to people who might otherwise purchase them. Many kitchen devices are also one trick ponies, designed for a very specific function and nothing else.

The term is also sometimes used to refer to commentators and academics who trot out the same material over and over again. A politician could also be accused of being a one trick pony if he or she focused exclusively on one issue to the detriment of others. While single minded pursuit of a goal might seem admirable, it can also suggest that someone is lacking a wider grasp of the world, which could ultimately prove to be a problem.

In music, a “one trick pony” is also known as a “one hit wonder.” In this sense, an artist or band gains popularity with a single song, and fails to repeat the success. The term can also be used to describe an artist or band with limited abilities; in this case, all of the band's songs tend to sound the same, and the artists rely on one gimmick in their performances to attract fans.