Earthing Electrode is a Metal Conductor which is used for Earthing . it can be a different material may be copper may be Gi, copper Bonded , zinc coating etc. in earthing we use this conductor to buried in the ground and channelized the leakage current through it

or 

Earthing electrodes are specifically designed and installed to improve a systems earthing. ... Earth electrodes include rods or pipes driven into the ground, metallic plates or mats buried in the earth or a copper wire ring encircling the structure.Jun 12, 2014