What is a Bubble Chart?
A bubble chart is a data visualization that displays multiple circles (bubbles) in a two-dimensional plot. It is a generalization of the scatter plot, replacing the dots with bubbles. Most commonly, a bubble chart displays the values of three numeric variables, where each observation's data is shown by a circle ("bubble"), while the horizontal and vertical positions of the bubble show the values of two other variables.
Source:
https://www.displayr.com/what-is-a-bubble-chart/