Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
There are many faces of Linux, a term which has come to mean many things. Underneath all the things that Linux is, it is an operating system kernel.
The term Linux also is applied to the popular GNU operating system (OS) built on top of the Linux kernel, often simply called the Linux OS. Then on top of that are the Linux-based distributions that usually and simply are called Linux distributions, such as Mandriva Linux, Red Hat Linux, or SUSE Linux.
There are lots of Linux-based, operating system, distributions and they wear many faces too.
One problem with all this nomenclature is that it is very confusing. How do you know when someone says Linux what they are talking about?