As definition of "Foo" has lot's of meanings:
bar, and baz are often compounded together to make such words as foobar, barbaz, and foobaz. www.nationmaster.com/encyclopedia/Metasyntactic-variable
Major concepts in CML, usually mapped directly onto XMLElements (to be discussed later). wwmm.ch.cam.ac.uk/blogs/cml/
Measurement of the total quantity of pasture in a paddock, expressed in kilograms of pasture dry matter per hectare (kg DM/ha) www.lifetimewool.com.au/glossary.aspx
Forward Observation Officer. An artillery officer who remained with infantry and tank battalions to set up observation posts in the front lines from which to observe enemy positions and radio the coordinates of targets to the guns further in the rear. members.fortunecity.com/lniven/definition.htm
is the first metasyntactic variable commonly used. It is sometimes combined with bar to make foobar. This suggests that foo may have originated with the World War II slang term fubar, as an acronym for fucked/fouled up beyond all recognition, although the Jargon File makes a pretty good case ... explanation-guide.info/meaning/Metasyntactic-variable.html
Foo is a metasyntactic variable used heavily in computer science to represent concepts abstractly and can be used to represent any part of a ... en.wikipedia.org/wiki/FOo
Foo is the world of dreams (no its not) in Obert Skye's Leven Thumps series. Although it has many original inhabitants, most of its current dwellers are from Reality, and are known as nits. ... en.wikipedia.org/wiki/Foo (place)
Also foo’. Representation of fool (foolish person), in a Mr. T accent en.wiktionary.org/wiki/foo
Resource: google