Foobar

Foobar is a placeholder name used in computing to illustrate code, data structures, or configuration examples without relying on real data. It appears with other generic terms such as foo and bar and is widely recognized in programming culture.

Historically, foo and bar are metasyntactic variables used in examples and tutorials since the early days of computer science. Foobar is a longer composite form that has appeared in many teaching materials and documentation to demonstrate interactions between components or functions.

In practice, foobar is used to name variables, functions, test data, or project names in examples. A typical usage might describe a function that takes foo and bar as inputs and returns foobar, or use foobar as a stand-in for a user’s data. These placeholders help readers focus on structure rather than specifics.

Variants and related terms include baz and qux, as well as more extended names like foobaz or foobarfoo. The term also appears in real-world products or projects, such as Foobar2000, a media player, and other software kits that adopt foobar as a project name.

See also Metasyntactic variable.