Public sector - is a portion of the economy composed of all levels of government and government-controlled enterprises. It does not include private companies, voluntary organizations, and households.
The general definition of the public sector includes government ownership or control rather than mere function and thereby includes, for example, the exercise of public authority or the implementation of public policy.
An NGO or non-governmental organization (NGO) is a group that functions independently of any government. It is usually non-profit. NGOs, sometimes called civil society organizations, are established on community, national, and international levels to serve a social or political goal such as a humanitarian cause or the protection of the environment.