Is Linux an operating systems

Answer 1

Linux is a kernel. It does not provide any other features of an operating system (such as an interface or programs). Linux is roughly the equivalent of ntoskrnl.exe in Windows 2000/XP/Vista. Complete operating systems containing the Linux kernel are usually referred to as "Linux distros."

Answer 2

Technically speaking, Linux is just the kernel (which is a critical part of an operating system).

Although it's "generally" okay to refer Linux as the operating system platform (which is GNU/Linux) because the name has been commonplace to refer to the entirety of Linux distributions. (mostly referring to GNU/Linux and not something like Android, which also uses the Linux kernel)