Part of a Pie Chart is a term used to describe a SEGMENT of a pie chart. A pie chart is a circular graph that is divided into sections, or segments, to represent the relative sizes of different parts of a whole. Each SEGMENT of the pie chart is labeled with a value, and the total of all the values in the chart should add up to 100%. Pie charts are used to visually represent data, and can be used to compare different parts of a whole.