Simple definition
A systemd target groups units to represent a startup or operational state, such as multi-user mode.
Purpose and use
A systemd target groups units to represent a system state or synchronization point.
How does it work?
Dependencies pull in other units; the target is generally not an executable program.
Example and verification
To understand startup, inspect required or wanted units and their explicit ordering.
Points to watch
A dependency does not necessarily establish execution order. Reaching a target does not prove that every application is functionally healthy.
In short
A target organizes units rather than replacing checks on its services.