If you work with a Linux distro such as AlmaLinux or Ubuntu, you will soon come across the term 'package'. Simply put, packages are ready-to-use installable software containers. They can be installed using a command that will look like this (in Ubuntu & Debian):
sudo apt -y install <packagename>In addition to the files of the relevant software, a package also contains metadata. The metadata describes the files in the package and indicates which other software must be present (dependencies) in order to be able to install and use a package.
This system uses repositories (also known as repo), which can be regarded as an archive / index of available packages. Your OS periodically retrieves the index of the packages in the repository. If additional software is needed (a dependency) to install your software, it can easily be found and installed in the repository's index.
The repositories also contain the versions of the software included therein. This also makes it easier to update software, because then, your installed software versions can be compared to the versions in the repository.