Stacked Bar Chart is neither Multi-set Bar Chart nor simple Bar Chart. Stacked Bar Chart is multiple datasets on top of each other in order to show how the larger category is divided into the smaller categories and their relations to the total amount.

Basically, they can be divided into two types:
1) Simple Stacked Bar Chart displays total value of the bar is all the segment values added together.
2) 100% Stack Bar Chart displays part to whole relationship in each group.