Longman Dictionary of Contemporary English
a. Of or relating to a public sector. n. 1 Any government and all entity that are controlled or funded by it and deliver public services. 2 The area of the nation's affairs under governmental rather than private control. 3 industries or services provided or funded by the government.
The public sector is the part of the economy concerned with providing various governmental services. The composition of the public sector varies by country, but in most countries the public sector includes such services as the military, police, infrastructure ( public roads, bridges, tunnels, water supply, sewers, electrical grids, telecommunications, etc.), public transit, public education, along with health care and those working for the government itself, such as elected officials. The public sector might provide services that a non-payer cannot be excluded from (such as street lighting), services which benefit all of society rather than just the individual who uses the service.
Businesses and organizations that are not part of the public sector are part of the private sector. The private sector is composed of the business sector, which is intended to earn a profit for the owners of the enterprise, and the voluntary sector, which includes charitable organizations.