No matter if you just started reading about Linux or have already installed a distribution of your choice, there's a good chance you've come across some of some of these words. They are essential to you unfolding your full Linux potential.
Kernel
If you've ever looked into Linux you've probably come across the term "Kernel". A kernel is a piece of software at the core of an operating system. It has complete control about everything in the system and handles interactions between hardware and software components.
Distribution
A Linux distribution, short distro, is an operating system composed of the Linux Kernel and additional software like a package manager. There's often also a GUI (Graphical User Interface) included. Common distributions include: Ubuntu, Debian, ArchLinux
Open source
When a program is open source, it means that everyone can look at the source code, change it and compile it for themself. This often also means, that it's free.
Command line
The command line is a text interface to your computer. You can open programs, modify files and folders, change system settings and a lot more.
Often referred to as shell, terminal, console and some other names, it can give appearance of being complex and confusing to use. That is why beginners are often scared from it and won't use it all. But the command line is a powerful tool that can make tasks easier (Yes, that's not a typo). Still one way or the other at some point in your Linux journey you'll have to use the command line.
Package manager
A package manager is a collection of tools that automates the installation, upgrade, configuring and removal of software. Programs that you install with it are called "Packages" hence the name. To install Firefox on Windows you would have to download the installer and install it. With a package manager on Linux it can be done with one command: sudo apt-get install firefox.
Desktop environment
A desktop environment, short DE, is a collection of software running on top of an operating system that makes up the desktop GUI (Graphical User Interface). It usually includes everything from how the windows feel and lock, to the style of files, icons, folders and the mouse pointer. On a Linux the DE can be freely changed. Popular names include: XFCE, KDE and GNOME.
Repository
A Linux repository is a storage location that contains essential and popular software for different Linux distributions and, each distribution has its own official repositories (also called standard-repositories). You can manage many packages (software) supported by your distribution and your system can install software from it. But what happens if I want to get some packages that are not in an official repository of my distro… it’s simple, you can add other repositories, not always recommended but if you decided to add a new repo it’s at your own risk.