• Bootloader

  Program (for example GRUB) which starts OS. Allows (if configured to do so) to choose OS to boot (as long as systems are installed in same boot mode - Legacy (BIOS) or UEFI).

• Desktop Environment (DE)

  A set of programs selected to provide common graphical user interface (GUI) to help user use their computer (desktop, file/web browser, media players). Examples: KDE Plasma GNOME XFCE

• Live Environment

  Linux started without changing content of hard disk, for example from installation media. Any changes are typically lost on power loss. Allows users to correct some problems or experiment and check hardware compatibility before installing specific distribution.

• Long-Term Support (LTS)

  Release which offers longer period of feature and security updates. Preferable over testing and normal term support releases.

• Operating System (OS)

  Main program which acts as a medium between hardware and user.

• Package

  A program compiled for use on specific environment (distributions' maintainers prepare packages ready to be used on their distribution).