pacemaker
(noun)
noun
1. a leading instance in its field
Similar word(s): pacesetter
Definition categories: thought, example, exemplar, model
2. a specialized bit of heart tissue that controls the heartbeat
Definition categories: body
3. an implanted electronic device that takes over the function of the natural cardiac pacemaker
Definition categories: man–made
4. a horse used to set the pace in racing
Similar word(s): pacer, pacesetter