Meanings
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1
noun
a small implanted electronic device that regulates an abnormal heartbeat
Surgeons fitted him with a pacemaker to keep his heart rhythm steady.
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2
noun
the specialized cells that naturally initiate and regulate the heartbeat, especially the sinoatrial node
Damage to the heart's natural pacemaker can produce an irregular rhythm.
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3
noun
a person or animal that sets the pace in a race, or a leading example that others follow
The experienced runner served as pacemaker for the first half of the race.
Thesaurus
Etymology
A compound of pace + maker. It first named a competitor who sets a race's pace; biology then applied the image to cells that set the heart's rhythm, and medicine to an electronic device that performs the same function.