Copula

What Does Copula Mean?
A statistical measure that represents a multivariate uniform distribution, which examines the association or dependence between many variables. Although the statistical calculation of a copula was invented in 1957, it was not applied to financial markets and finance until the late '90s.  

Investopedia explains Copula
Copulas are a mathematical tool used in finance to help identify economic capital adequacy, market risk, credit risk and operational risk. Interdependence of returns of two or more assets is usually calculated using the correlation coefficient. However, correlation only works well with normal distributions, while distributions in financial markets are mostly skewed. The copula, therefore, has been applied to areas of finance such as option pricing and portfolio value-at-risk to deal with the skewness.