pacemaker

A pacemaker is most commonly a small medical device placed in the chest to help control the heartbeat. If the heart beats too slowly or unevenly, it sends gentle electrical signals to help keep the rhythm steady. You can think of it as a quiet helper that keeps the heart on time.

The word is also used in sports. In a race, a pacemaker is a runner or cyclist who leads for part of the event so others can keep a planned speed. More broadly, it can sometimes mean a person or group that leads the way for others. So whether it is helping a heart or setting the speed in a race, a pacemaker helps keep things moving at the right pace.

A pacemaker is most often known as a small electronic device that is placed in the body to help control a slow or irregular heartbeat. The heart has its own natural pacemaker, but sometimes that system does not work well enough because of illness, age, or damage to the heart. In those cases, this device watches the heart's rhythm and sends small electrical signals when needed, helping the heart beat in a steadier and safer way. You might read about someone receiving one after a heart problem or as part of a planned medical procedure.

Outside medicine, the word also appears in sports. In running or cycling, a pacemaker, often called a pacer, goes in front for a while so others can follow a target speed. This is especially common in long races where athletes want to keep a strong, even pace. In this sense, the pacemaker does not just lead; it helps shape the rhythm of the event.

The word can also be used more generally for someone or something that leads the way, though this use is less common in everyday speech than the medical and sports meanings. In all of its main uses, the idea is similar: a pacemaker sets or supports the pace, whether that pace is the beat of a heart or the speed of a race.