e ‧ lec ‧ trode /ɪˈlektrəʊd $ -troʊd/ BrE AmE noun [countable]
[ Date: 1800-1900 ; Origin: electro- + Greek hodos 'way, path' ]
a small piece of metal or a wire that is used to send electricity through a system or through a person’s body:
The monkeys have electrodes implanted into the brain to measure their brain activity.