A pulsation is a rhythmic beating or throbbing movement, like the steady pulse you can feel in your wrist when you press two fingers against it. Your heart creates pulsations as it pumps blood through your body: expand, contract, expand, contract, over and over in a regular pattern.

The word describes any kind of regular, repeating motion that beats or throbs. Scientists observe pulsations in certain stars that grow brighter and dimmer in steady cycles. You might feel pulsations in your temples when you have a headache, or notice the pulsation of music with a strong bass beat. Emergency vehicle lights create pulsations of red and blue.

Pulsation suggests something rhythmic rather than random or jerky. A flickering candle doesn't pulsate, but a jellyfish does as it rhythmically expands and contracts to move through water. Engineers study the pulsations in engines and machinery to make sure everything is working smoothly. When something pulsates, it has a steady beat that you can almost predict, like a drum keeping time or your own heart reminding you it's always working.