correlation, correlativity -- (a reciprocal relation between two or more things)
correlation coefficient, coefficient of correlation, correlation -- (a statistic representing how closely two variables co-vary; it can vary from -1 (perfect negative correlation) through 0 (no correlation) to +1 (perfect positive correlation); "what is the correlation between those two variables?")
correlation, correlational statistics -- (a statistical relation between two or more variables such that systematic changes in the value of one variable are accompanied by systematic changes in the other)
(Sound)
