an open-source version of the UNIX operating system
"Many developers choose Linux as their preferred open-source version of the UNIX operating system because it is free and highly customizable."
Any unix-like operating system distro that uses the Linux kernel.
"After installing Ubuntu, I discovered it was just another popular distribution running on the Linux kernel."
In plain English: Linux is an open-source operating system that runs many computers and devices around the world.
"Many people choose Linux to power their home computers and servers because it is free and open source."
An open-source computer operating system kernel.
"Many developers choose Linux as an open-source computer operating system kernel because it is free to modify and distribute."
The word Linux is a blend combining the first name of its creator, Linus Torvalds, with the operating system family known as Unix. It was coined to reflect both his authorship and the technical lineage of the software.