is varience and variability equal?

Anish,

In Statistics, by variability, we mean how closely or how distantly the different values are located to the mean. In case the values are close to the average value, we say there is 'low variability'. On the other hand, if the values are distantly located, then we say the series depict 'high variability'. Thus, to judge the extent of variability in the data, measures of dispersion are used.

One of the measures of dispersion is variance. Variance is the square of standard deviation and is defined as the average squared distance between the mean and each item in the distribution. It is denoted by s², while population variance is denoted by σ² . 
Algebraically,

                                                            $\boxed{ Variance\left(s^2\right)=\frac{\sum (X_i-\overline{X})}{n} }$