A lot vs. Alot: 9 Grammatical Pitfalls
early 15c., from Middle French pulsation (14c.) and directly from Latin pulsationem (nominative pulsatio) "a beating or striking," noun of action from past participle stem of pulsare "to beat, strike, push against' hammer, keep hitting," figuratively "drive forth, disturb, disquiet," frequentative of pellere (past participle pulsus) "to beat, strike" (see pulse (n.1)).
pulsation pul·sa·tion (pŭl-sā'shən)
The act of pulsating.
A single beat, throb, or vibration.