What is the difference between the bar graph and chart?

A bar graph is a type of chart in which data (usually absolute quantities) is shown as bars either vertically or horizontally. Each bar can further be split up into sections.

Another chart type is the pie chart in which data (most often parts of a whole, percentages, etc.) is shown as wedges of a circular "pie".

Another chart type is a scatter plot where data is plotted as discrete points perhaps connected with a trend line.