Q:

Where does the word GNU come from?

GNU is a Unix-like operating system. 
That means it is a collection of many programs: applications, libraries, developer tools, even games.
The development of GNU, started in January 1984, is known as the GNU Project. Many of the programs in GNU are released under the auspices of the GNU Project; those we call GNU packages.
But where does the GNU word come from?

A:

GNU is a recursive acronym, GNU's Not UNIX
It was chosen because:

The name “GNU” was chosen because it met a few requirements; first, it was a recursive acronym for “GNU's Not Unix”, second, because it was a real word, and third, it was fun to say (or Sing).

See this GNU webpage for more historical information on the the name.

A:

"Gnu" itself, meaning a type of African antelope, also called a "Wildebeast", is from the Khoikhoi language of Africa, the initial "G" indicating the glottal stop that is exensively used in Khoikhoi.

