Definitions for "Heteroscedasticity"
A scatter-plot or residual plot shows heteroscedasticity if the scatter in vertical slices through the plot depends on where you take the slice. Linear regression is not usually a good idea if the data are heteroscedastic.
Time-varying, or time-dependent, variance.
The absence of homogeneity of variance. See HOMOGENEITY OF VARIANCE.
Keywords:  volatility, constant, non
Non-constant volatility.