DC powers battery operated vehicles and other machines and electronics. Converters can change AC to DC and vice versa. High-voltage direct current transmission uses big converters. That’s it an electrical curcit.
Electric circuit is used by electrons from a current source or voltage power.
To prevent the danger of electrical shock and the possibility of electrocution, ground fault interrupts devices detect open circuits to earth ground in attached electrical or electronic devices.
The point where those electrons enter an electrical circuit is called the "source" of electrons. The point where the electrons leave an electrical circuit is called the "return" or "earth ground". The exit point is called the "return" because electrons always end up at the source when they complete the path of an electrical circuit.