What is Linux?

The word "Linux" describes a couple of things. Most accurately, the word "Linux" describes an operating system kernel -- that is, the low-level part of an operating system that does all the hard work of talking to the computer's hardware, managing memory and devices, and generally doing the grunt work. Unless you are an advanced user, or you run into some sort of hardware or software problem, you'll almost never interact or even need to think about the kernel itself.

While it's a very important part of the system, it's not something that users interact with directly. Instead, you'll be working with what are referred to as "user-space" programs -- so called because users actually work with the programs directly. When a vendor or project bundles the Linux kernel and a bunch of user-space programs together in a way that's useful to end users, that's called a Linux distribution, often just "Linux" for short -- because Linux is at the heart of the whole thing to begin with, and saying "Linux distribution" every time is a bit long winded. Generally speaking, when people say something like "I use Linux," or "have you tried Linux?" they're not just talking about the kernel, they're talking about a Linux distribution.