heartbeat

Etymology

From heart + beat.

noun

1. One pulsation of the heart; especially an irregular one, hence the emotion which causes it.
   The policeman waited for a heartbeat in vain.
   He alone gives me such heartbeats.
2. The rhythm at which a heart pulsates, a cardiac indicator.
   If your heartbeat doesn't normalize soon, consult a doctor!
3. A driving impulse or vital force; the vital center of something.
   Music is the heartbeat of the people.
   Dream Body Recovery is just one of countless recovery houses that have cropped up in Miami, which has become the heartbeat of the B.B.L. boom in the United States. The average price of a B.B.L. nationwide is around $5,000, according to the American Society of Plastic Surgeons. 2022-05-11, Sandra E. Garcia, “Butt Lifts Are Booming. Healing Is No Joke.”, in The New York Times Magazine
4. A very short space of time; an instant.
   The ambulance arrived in a heartbeat.
   Cause I love you more than life Take a bullet for you I swear, I swear In a heartbeat 2014, “Bullet”, Robbie Williams et al. (lyrics)
5. (computing) A periodic signal generated by hardware or software to indicate normal operation or to synchronize other parts of a system.