Public Good

A public good is a product or service that is available for everyone to use, and its consumption by one person does not reduce its availability for others. Key features include non-excludability—meaning no one can be easily prevented from using it—and non-rivalry—where one person's use doesn't diminish its usefulness to others. Examples include clean air, street lighting, and national defense. Because they benefit all members of a community, public goods are often provided or funded by the government or through collective efforts, as private markets may struggle to supply them effectively.