Linux is a group of open-source Unix-like operating systems based on Linus Torvalds’ Linux kernel, which was initially released on September 17, 1991. A Linux distribution is a collection of Linux packages.
The Linux kernel, as well as other system software and libraries, are included in distributions, many of which are given by the GNU Project. Many Linux versions use the term “Linux,” however the Free Software Foundation uses the term “GNU/Linux” to underline the importance of GNU software, which has sparked some debate.
Debian, Fedora, and Ubuntu are all popular Linux distributions. Red Hat Enterprise Linux and SUSE Linux Enterprise Server are two commercial distributions. A windowing system like X11 or Wayland, as well as a desktop environment like GNOME or KDE Plasma, are included in desktop Linux distributions. Server distributions may or may not include graphics, or may include a solution stack such as LAMP. Anyone can produce a distribution for any purpose because Linux is freely redistributable.