target unit
also: target
In systemd, a target unit is a special unit file that groups other units together and represents a system state or runlevel, such as multi-user.target or graphical.target.
A target unit is a systemd unit type (with a .target file extension) that acts as a logical grouping of other units to define a system state or boot goal. Target units do not perform actions themselves but instead declare dependencies on other units—services, sockets, devices, and mounts—that should be started together.
Target units replace the traditional SysV runlevels. For example, multi-user.target represents a multi-user command-line system state and typically depends on services like networking, logging, and user login facilities. When you boot to a target, systemd starts all units required by that target.
You can view the current active target with systemctl get-default and switch targets with systemctl isolate graphical.target. Common targets include graphical.target (with GUI), multi-user.target (CLI only), and rescue.target (minimal recovery mode).