Public Good

In economics, a public good is a good that is both non-excludable and non-rivalrous in that individuals cannot be effectively excluded from use and where use by one individual does not reduce availability to others... This is in contrast to a common good which is non-excludable but is rivalrous to a certain degree. https://en.wikipedia.org/wiki/Public_good

cf Intellectual Property, Commons, infrastructure, open-source

Excludable Non-Excludable
Rivalrous Private Goods Commons-pool
Non-rivalrous Club-goods (or toll goods) Public goods

Edited:    |       |    Search Twitter for discussion