$ man systemd
NAME
systemd, init — systemd **system** and service manager
managing your whole Linux system in an unified way, with a single configuration language to learn, a single syntax for commands, and a shared framework allowing to refer to systemd domain objects (units) from everywhere where they can be relevant (journal, network, fstab, etc) is the raison d'être of systemd. It's why it has been created.
Just saying the word system does not mean anything. Maybe my system encompasses more than a single machine, maybe it encompasses more than just silicon. Same with units. It is a word that means as little as possible. You did not answer my question, you just regurgitated vague and useless documentation.
