The term pacemaker has multiple meanings:
- In sports, a pacemaker or pacer is a competitor who enters an athletics race with little or no intention of winning, but purely to set a fast pace for other competitors to follow.
- In biology, the cardiac pacemaker is a group of cells within the heart that together initiate contractions and set the pace of beating.
- An artificial pacemaker may be implanted to provide proper rhythm when the body's natural pacemaker does not function properly.