A contour plot is a graphical representation used to display three-dimensional data in two dimensions. It uses contour lines to connect points of equal value, allowing viewers to visualize the shape and gradient of a surface. This type of plot is commonly used in fields like geography, meteorology, and engineering to illustrate variations in data such as elevation, temperature, or pressure. In a contour plot, the x and y axes represent two independent variables, while the contour lines indicate the levels of a dependent variable. The spacing between these lines reveals how steep or flat the surface is; closer lines indicate a steep gradient, while wider spacing suggests a gentle slope.