Meaning

noun a reciprocal relation between two or more things

noun 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)

noun 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

originFrom Middle French corrélation. Morphologically correlate + -ion.

Etymology from Wiktionary, CC BY-SA 3.0