Definition of Public and Private Goods
A public good is a good that fulfills both of the following two criteria: Nonrival. One individual’s consumption of the good does not affect any other individual’s consumption of the same unit of the good. Examples include lighthouses, television, parks, military defense, and streets with little traffic.
Nonexclusive . It is not possible to exclude anyone from consuming the good. The examples above are usually nonexclusive. A private good is, instead, a good that does not fulfill any of the two criteria, i.e. one that is both rival and exclusive. Most goods are private goods.