- negative / positive externalities -> cost or benefits that affect other external to a choice or trade
ex: if you drive. car, you need to pay for insurance, repairs...etc, and also it will be a damage to the environment
-> unintended costs imposed on third parties due to economic activities, often leading to overproduction or overconsumption of related goods. [negative externalities]
ex: beautiful garden not only pretty but also attractiing
-> feeling that garden gives, nintended benefits created for third parties, oft