>>LinuxThe proper term is GNU.
The GNU project started developing an operating system in about '83. They made many central components. The kernel was missing. In about '92 Linux (a kernel) came around and once it was licensed under the GNU license people started using GNU with Linux. This means the operating system is GNU, with Linux as the kernel.
If you think the kernel is more central/important/big than other parts of an operating system, you're mistaken. In terms of size, surely
X.Org is huge as well, and it's very central too, yet you won't hear people call the operating system
X.Org, or mention
X.Org in the name at all. This is because it's only one component, although it does many things including talking to hardware at the low-level. Similarly, the kernel is just one component that talks to hardware and does some other important low-level things. But none of these are more important than the tasks of GNU components such as GCC/Autotools/Yacc/Bison/etc. (the compiler and related tools used to build everything), Glibc (the C library which virtually *all* software on the system links against, including
X.Org), GRUB (the bootloader that loads the kernel in first place), GNU Bash (the login shell!), GNU coreutils/findutils/grep/sed/awk, and many other such tools which make the system POSIX compliant and are necessary for most software and scripts to run on the operating system at all...
And if you say "but those components can be replaced", then obviously
X.Org and Linux can also be replaced. Wayland based systems are on the way, and there is already e.g. Debian GNU/kFreeBSD which is the Debian GNU system running on the FreeBSD project's kernel.
To summarize, in terms of project/culture GNU is the project and operating system; and in terms of significance and irreplaceability of components, GNU components are definitely not any less important than
X.Org and Linux.
Therefore, it makes most sense to say GNU, not Linux or GNU/Linux.
