Linux
In plain terms
A widely-used open-source, Unix-like operating system kernel.
Going deeper
Linux is a free, open-source kernel powering servers, cloud, Android, and embedded devices, central to modern computing. It dominates infrastructure.
Under the hood
Distributions (Ubuntu, Debian, RHEL) bundle the kernel with tools; runs most of the internet and cloud.
Examples
Servers, cloud, Android, supercomputers, Ubuntu, embedded devices.
Think of it like...
Like a free, community-built engine that powers a huge share of the world's computers.