pie chart
a graphic display in which a circle is cut into wedges, with the area of each wedge being proportional to the percentage of cases in the category represented by that wedge. For example, a researcher might use a pie chart to present the results of a survey on the sources of psychology-related literature used by the general public, with each wedge representing the percentage of respondents citing a particular source, such as an advice column, the Internet, a self-help book, a popular magazine, and academic literature. A pie chart generally works best when there are not many categories (with thin wedges) being shown. A downside of the graphic is that it is not very efficient because it uses significant space to show the frequencies of a single variable.