Electric circuit is used by electrons from a current source or voltage power.
Electrical and electronic circuits can be complicated. Making a drawing of the connections to all the component parts in the circuits load makes it easier to understand how circuit components are connected.
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.
Electric circuitry is a key component of the National Curriculum, particularly from ages 14, Key Stages 4 onwards. However this is a difficult concept to teach because it of its abstract nature.