If the correlation coefficient between two variables, x and y, equals zero, what can be said of the variables x and y

If the correlation coefficient between two variables, x and y, equals zero, it is said that the variables are not related. 
We can define a correlation coefficient as the degree to which two variables' movements are associated and the range of values for the correlation coefficient is -1 to 1. When its value is 1, it means it is a perfect positive correlation and when it value is -1, it means it is a perfect negative correlation.