What is the best definition for public goods?

Public goods are commodities or services that are made available to all members of a society without exclusion and for which use by one individual does not reduce availability to others. They are characterized by non-excludability and non-rivalry, meaning that individuals cannot be effectively excluded from using them, and one person's consumption does not diminish another's ability to use them. Examples include clean air, national defense, and public parks. Because of these characteristics, public goods are often provided by the government or funded through taxation.