The Marginal Rate of Substitution (MRS) measures how much of one good a consumer is willing to give up to obtain an additional unit of another good while maintaining the same level of satisfaction. It reflects the trade-off between two goods, indicating the rate at which a consumer substitutes one for the other. MRS is often represented in the context of a consumer's preferences and is derived from their indifference curves, which illustrate combinations of goods that provide equal utility. A higher MRS suggests that a consumer values one good significantly more than the other at that point on the curve.