Import Quota
Plain definition
A government-imposed limit on the quantity (or value) of a good that may be imported over a period. Unlike a tariff, a quota caps volume directly, which can push domestic prices even higher when demand is strong.
In economics
Quotas protect domestic producers like tariffs do, but the price-gap profit (quota rent) goes to whoever holds the import licenses rather than to the government as revenue. Quotas are generally more distortionary than equivalent tariffs because they freeze import competition regardless of price signals.
Example
The US long maintained quotas on imported sugar: only a fixed tonnage could enter at low duty, keeping domestic sugar prices far above the world price and boosting domestic growers' incomes.
Quotas are often treated as just 'another tariff,' but the key difference is who gets the windfall. Tariff revenue goes to the treasury; quota rents go to license holders -- which is why quotas invite lobbying and rent-seeking over license allocation.