English word kurtosis comes from Ancient Greek κυρτός

Detailed word origin of kurtosis

Dictionary entry	Language	Definition
κυρτός	Ancient Greek (grc)
κύρτωσις	Ancient Greek (grc)
kurtosis	English (eng)	(statistics) A measure of "heaviness of the tails" of a probability distribution, defined as the fourth cumulant divided by the square of the variance of the probability distribution.