Correlation

n. mutual relation, mutual connection (between two or more things); similarity

This article is about the correlation coefficient between two variables. The term correlation can also mean the cross-correlation of two functions or electron correlation in molecular systems. In probability theory and statistics, correlation, also called correlation coefficient, indicates the strength and direction of a linear relationship between two random variables. In general statistical usage, correlation or co-relation refers to the departure of two variables from independence. In this broad sense there are several coefficients, measuring the degree of correlation, adapted to the nature of data.
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Noun
1. a reciprocal relation between two or more things
(synonym) correlativity
(hypernym) reciprocality, reciprocity
(derivation) correlate
2. 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?"
(synonym) correlation coefficient, coefficient of correlation
(hypernym) parametric statistic
(hyponym) product-moment correlation coefficient, Pearson product-moment correlation coefficient
(derivation) correlate
(classification) statistics
3. 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
(synonym) correlational statistics
(hypernym) statistics
(hyponym) curvilinear correlation, nonlinear correlation, skew correlation
(part-holonym) correlational analysis
(derivation) correlate

n. correlation, correlative, interrelation

(n.)
Reciprocal relation; corresponding similarity or parallelism of relation or law; capacity of being converted into, or of giving place to, one another, under certain conditions; as, the correlation of forces, or of zymotic diseases.