kurtosis
noun
kur·to·sis (ˌ)kər-ˈtō-səs 
: the peakedness or flatness of the graph of a frequency distribution especially with respect to the concentration of values near the mean as compared with the normal distribution
Word History
Etymology
Greek kyrtōsis convexity, from kyrtos convex — more at curve
First Known Use
1905, in the meaning defined above