A pictorial diagram is a visual representation of information, usually in the form of a GRAPH or CHART. It is used to illustrate data or concepts in a way that is easy to understand. A GRAPH is a diagram that shows the relationship between two or more variables, while a CHART is a graphical representation of data, usually in the form of a table or bar GRAPH. Both are useful tools for conveying information in a concise and visually appealing way.