A bubble chart is a type of data visualization that displays three dimensions of data. Each point on the chart represents an item, with the position on the x and y axes indicating two variables, while the size of the bubble represents a third variable. This allows viewers to quickly grasp relationships and trends among multiple data points. Bubble charts are commonly used in fields like business, economics, and science to illustrate complex data sets. They can help identify patterns, outliers, and correlations, making them a valuable tool for data analysis and decision-making.