- a system in which organizations and countries are permitted to produce a set amount of carbon dioxide emissions and other atmospheric pollutants, with the provision that those who do not produce their entire allowance may sell their remaining capacity to those who have exceeded their allowed limit (often used attributively): a cap-and-trade program.
- denoting a scheme which allows companies with high greenhouse gas emissions to buy an emission allowance from companies which have fewer emissions, in a bid to reduce the overall impact to the environment
