pacemaker

pace·mak·er

noun \ˈpā-ˌsmā-kər\

Definition of PACEMAKER

1

: a group of cells or a body part (as the sinoatrial node of the heart) that serves to establish and maintain a rhythmic activity

2

: an electrical device for stimulating or steadying the heartbeat or reestablishing the rhythm of an arrested heart—called also pacer