What does GNU/Linux mean?
GNU/Linux is a combination of operating system components and services that together create the Linux operating system. GNU/Linux is considered the first version of Linux that was built alongside the components and services of GNU and the Linux kernel.
Techopedia explains GNU/Linux
GNU/Linux is primarily referred to as the combination of the Linux kernel with the GNU OS components that form the complete Linux operating system. According to GNU the bulk of the work, except the Linux kernel itself, was done by the GNU community. The whole system as a whole is largely considered the work of GNU, but it is complimented with the Linux Kernel.
The GNU Project initially created the components and services that were to be used by UNIX, which were later embedded with the Linux kernel to create the GNU/Linux operating systems.