BASIC DEFINATIONS 

specimen:

1. an individual animal, plant, piece of a mineral, etc. used as an example of its species or type for scientific study or display.

   "specimens of copper ore"

   • an example of something regarded as typical of its class or group.
     "a specimen paper of the new test"
   • a sample for medical testing, especially of urine.
     
     
2. informal

   used to refer humorously to a person or animal.

   "Carla could not help feeling a degree of reluctant admiration for this odd female specimen"

electrode :

a conductor through which electricity enters or leaves an object, substance, or region