foo
n. countablen. a name used by programmers for something when the real name does not matter. It is a placeholder you use while writing or testing code.
n. a metasyntactic variable used as a placeholder name for any part of a program, such as a variable, function, or file. Often paired with 'bar' in technical documentation to demonstrate logic without specific context.
The programmer named the test file foo.txt.
When explaining the new function, the instructor used foo as a temporary variable name to keep the focus on the logic.
In many early programming tutorials, foo serves as the primary placeholder, followed by bar and baz, establishing a naming convention that persists in modern documentation.
From Mandarin 府 (fǔ).
From Chinese 福 (fú, “fortunate; prosperity, good luck”), via its use as 福星 (Fúxīng, “Jupiter”) in Chinese statues of the Three Lucky Stars, picked up from c. 1935 as a nonsense word in Bill Holman's Smokey Stover comic strip, whence it was picked up by Pogo, Looney Tunes, and others. Used by Jack Speer as the name of a mock god of mimeography in the 1930s. Popularized in computing contexts by the Tech Model Railroad Club's 1959 Dictionary of the TMRC Language, which incorporated it into a parody of the Buddhist chant om mani padme hum, possibly under the influence of WWII military slang FUBAR, which had been repopularized by Joseph Heller's Catch-22.
A minced form of fuck.
Commonly used in technical documentation and code snippets; informal and humorous in register.