A meta package is a way to install ‘lots’ of software. It is a bundle of packages installed with one command.
Read all about it on the wiki of Arch Linux.
We install all the wallpapers (500MB) with this single command:
sudo pacman -S arcolinux-wallpapers-submicron-3840x2400-wquxga-git-meta
Want to create a meta package for yourself – read more here