PACEMAKER

Definition

1. noun a leading instance in its field. — synonyms: pacesetter
2. noun a specialized bit of heart tissue that controls the heartbeat. — synonyms: cardiac_pacemaker, sinoatrial_node, SA_node
3. noun an implanted electronic device that takes over the function of the natural cardiac pacemaker. — synonyms: artificial_pacemaker
4. noun a horse used to set the pace in racing. — synonyms: pacer, pacesetter