Linux is effectively made up of two parts. First is the kernel, the code that interacts with the computer’s hardware, and then there is the desktop environment, the software that the user interacts with (and in turn, what interacts with the kernel).
The Linux kernel is under constant development, with new releases available every few weeks. Your Linux distribution might not make every new update available in the software repositories, but if you’ve had a particular distribution installed for half a year or so, it’s likely you’ve managed to accumulate 3 or 4 kernels, maybe more.
