systole

noun

1. (countable, uncountable)The rhythmic contraction of the heart, by which blood is driven through the arteries.

   “[…] I did almoſt beleeve, that the motion of the Heart vvas knovvn to God alone: For neither could I rightly diſtinguiſh, vvhich vvay the Diaſtole and Systole came to be, nor vvhen nor vvhere the dilation and conſtriction had its exiſtence.”

   “A double systole catapulted him into full consciousness again, and he promised his uncorrected self that he would limit his daily ration of cigarettes to a couple of heartbeats.”

   “There is no essential virtue in comfort. To be relaxed is good if it is part of a process of systole and diastole. Relaxation comes between phases of tenseness.”

2. (countable, rhetoric, uncountable)A shortening of a naturally long vowel.
3. (countable, uncountable)The shortest noncontractible loop on a compact metric space.
4. (countable, uncountable)The contraction of the contractile vesicles in certain algae, plasmodia, and zoospores.