A bar chart is a visual representation of data that uses rectangular bars to show the values of different categories. Each bar's length or height corresponds to the quantity it represents, making it easy to compare different groups at a glance. For example, a bar chart could display the number of apples, bananas, and oranges sold in a week, with each fruit represented by a separate bar. Bar charts can be oriented either vertically or horizontally, depending on the data being presented. They are commonly used in various fields, such as business, education, and science, to illustrate trends and make data more accessible. By using colors and labels, bar charts help viewers quickly understand complex information.