A limit on the amount of imported goods that can come into a particular country during a given period of time.
Peter Dungan, Toronto PPG1002H, and
Mankiw, N., R. Kneebone, K. McKenzie and N. Rowe. Principles of Macroeconomics, 4th ed. Nelson College Indigenous, 2007.
From International Trade Theory and Policy - Chapter 10-2:
“There are two basic types of quotas: absolute quotas and tariff-rate quotas. Absolute quotas limit the quantity of imports to a specified level during a specified period of time. Sometimes these quotas are set globally and thus affect all imports while sometimes they are set only against specified countries. Absolute quotas are generally administered on a first-come first-served basis. For this reason, many quotas are filled shortly after the opening of the quota period. Tariff-rate quotas allow a specified quantity of goods to be imported at a reduced tariff rate during the specified quota period.”
Suranovic, Steven. International Trade Theory and Policy, Chapter 10-2. Accessed online at http://internationalecon.com/Trade/Tch10/T10-2.php.