Confusion regarding correlation and correlation coefficient Can somebody provide an intuitive difference between correlation and correlation coefficient? During learning of weights of neural network, I want to show how closely the estimated weights are to the known true weights. For this, I was thinking of using the correlation measure. If they are correlated then the value will be close to one. But I am not sure, if it should be the correlation or the correlation coefficient. 
Also, what is the difference between the two formula wise and physical meaning wise. Thank you
 A: 
Can somebody provide an intuitive difference between correlation and correlation coefficient? 

The word 'correlation' has (i) several specific technical senses (most usually the Pearson product-moment correlation, plus many other measures that get labelled as one or another kind of 'correlation' in different contexts), as well as (ii) a more general sense (implying some kind of association, usually monotonic, but without needing any specific 'formulaic' sense of the word).
In the most common usages of the terms, "correlation" and "correlation coefficient" mean the same thing - the Pearson product-moment correlation.
However, it is certainly possible for a single source using both terms to be attempting to draw a distinction, and in that case, for example, it might be that the second form (correlation coefficient) implies one of the mathematically defined technical senses I mentioned in (i), while the first might only refer to the more abstract/general sense of association.
Both senses are discussed here.
If you're referring to a particular use or uses of the terms, you'll need to provide some context, such as a direct quote (with source(s)).
