Return current is the current through the ground. Looking at the ckt as a loop the current is seen looping around source to the circuit to load and back to ground ..thats the return path for the current..hence return current.
You turn on your light at home, this is fed current from the power plant via a wire (live/hot etc).
You pay for this current.
Then there is another wire (nuetral/return etc) that goes back to the power station (eventually) that carries the current back to them.
You need both wires to complete the circuit for your light bulb.
You do not get a refund for giving them back the current.
Similar thing happens on PCB etc, component needs current so it draws it from a source, but it needs a return current path to send the current back to the source when it has finished with it.
Return current is the return path to complete the ckt also to folllow the conservation of law
Return current is the current through the ground. Looking at the ckt as a loop the current is seen looping around source to the circuit to load and back to ground ..thats the return path for the current..hence return current.