Total utility refers to the overall or total level of happiness or satisfaction that a consumer experiences by consuming a certain amount of a good or service. While marginal utility measures the change in (total) utility of consuming one additional unit, total utility measures the total level of happiness associated with the consumption of a certain quantity of the good.

Trade barriers refer to the obstacles that are put in place by governments to limit free trade between national economies. Trade barriers are thus essentially interventions in markets that happen to operate internationally. Trade barriers include tariffs (taxes) on imports (and occasionally exports) and non-tariff barriers to trade such as import quotas, subsidies to domestic industry, embargoes on trade with particular countries (usually for geopolitical reasons), and licenses to import goods into the economy.

A tradeoff refers to a situation in which in order to come closer to reaching one objective you must sacrifice another. In other words, when people or societies are facing a tradeoff, two or more goals are at odds and cannot be satisfied simultaneously. Any progress towards one of the goals is (at least partially) offset by a deterioration of the prospects of reaching another goal.