What is the extra satisfaction gained from consuming one more unit of a good or service called?

The extra satisfaction gained from consuming one more unit of a good or service is referred to as marginal utility. This concept is central to understanding consumer behavior in economics. Marginal utility helps to illustrate how the satisfaction or utility that a consumer derives from each additional unit of a good can change based on consumption levels.

When analyzing consumer choices, it's important to note that as a person consumes more units of a good or service, the additional satisfaction gained from each new unit tends to decrease. This is known as the law of diminishing marginal utility. While total utility represents the overall satisfaction a consumer gets from all units consumed, marginal utility specifically focuses on the change in satisfaction between consuming one more unit.

Diminishing returns, on the other hand, is a term often used in production contexts rather than consumption, indicating that adding more of one factor of production while holding others constant will eventually yield lower per-unit returns. Supply relates to the availability of goods in the market and is not concerned with individual consumer satisfaction levels but rather the quantity producers are willing to sell at different prices.

Thus, marginal utility is the correct term that describes the additional satisfaction from consuming one more unit, illustrating an essential principle in consumer choice theory and economics in general.