systemd is a suite of basic building blocks for a Linux system. It provides a system and service manager that runs as PID 1 and starts the rest of the system.
systemd provides aggressive parallelization capabilities, uses socket and D-Bus activation for starting services, offers on-demand starting of daemons, keeps track of processes using Linux control groups, maintains mount and automount points, and implements an elaborate transactional dependency-based service control logic.
Other parts include a logging daemon, utilities to control basic system configuration like the hostname, date, locale, maintain a list of logged-in users and running containers and virtual machines, system accounts, runtime directories and settings, and daemons to manage simple network configuration, network time synchronization, log forwarding, and name resolution.
Not every term, certainly. But the first paragraph is a good at describing the primary purpose. And the last paragraph shows the breadth of services provided. I shared it thinking it could be the basis for further learning, or exploration of the project website to go and read more about it.
The https://systemd.io/ main page has a pretty succinct answer to this:
If someone has to ask what systemd is, do you expect him / her to understand this answer?
Not every term, certainly. But the first paragraph is a good at describing the primary purpose. And the last paragraph shows the breadth of services provided. I shared it thinking it could be the basis for further learning, or exploration of the project website to go and read more about it.