Question

difference between earthing and grounding

Answer 1

In electronic circuits, grounding is usually defined as the point of zero potential. In other words, we set that to mean zero and that become the reference point for other voltages on your circuit board, which may be either positive or negative relative to GND. 

Earthing is a safety device used to prevent a shock due to leakages arising from weak insulation, breaking of the element or otherwise. The metal bodies of appliances handled like the electric iron, kettle or refrigerator must be earthed, that is, connected to a pipe leading deep into the earth on to a metal plate.