indifference surface

An indifference surface is a concept in economics that represents all combinations of two goods or services that provide a consumer with the same level of satisfaction or utility. Think of it as a “contour line” on a map showing options that are equally desirable to the person. If you move along this surface, your overall happiness remains unchanged, even though the amounts of the two items may change. It helps to visualize how consumers make choices to maximize satisfaction given their preferences and constraints.