cumulant
n. one of a set of values that describes the basic nature of a distribution. A cumulant is similar to and a logarithmic function of a moment of a distribution, especially for the first few values. The first cumulant (like the first moment) is concerned with the mean or average of a set of numbers, the second cumulant (like the second moment) refers to the variance or degree of spread in a set of numbers, and the third cumulant (like the third moment) indicates the skewness or degree of lopsidedness in a set of numbers. Cumulants and moments may differ beyond these initial values, and statistical methods generally are concerned only with the first three cumulants or moments of a distribution, as well as the fourth moment, kurtosis.