Definition - What does Foobar mean?
Foobar is a slang term used in the IT world as a placeholder to refer to generic examples or temporary files or programs that are to be deleted. The technical term for a word like foobar is a metasyntactic variable. These types of terms are used to name variables, programs or other parts of code.
Techopedia explains Foobar
A placeholder usually plays a role in situations where a programmer or developer may need to name a variable or other item, but may not have a name in mind. Where naming becomes extremely arbitrary, developers have come up with convenient defaults. One of these is foobar. Another is "foo", the first syllable of foobar, where bar is used as a second placeholder. So a temporary file may be named foobar.txt, foobar.jpg, etc.
It’s important not to confuse foobar with a similar term, fubar, which developed in the U.S. military. Fubar describes a chaotic and problematic situation; fubar has not such connotation in IT. It’s also useful to note that although foobar is an arbitrary placeholder, it has become popular enough to be used in naming some technologies, such as foobar2000, a freeware audio player for Windows.