green belt

Từ điển Oxford Advanced Learner 8th

ˌgreen ˈbelt [green belt] BrE NAmE noun uncountable, countable, usually singular (especially BrE)
an area of open land around a city where building is strictly controlled
•New roads are cutting into the green belt.
•Green belt development is carefully regulated.

Culture:
In Britain green belts are created to make sure that towns do not become too big and that there is some countryside for the people from the towns to enjoy. There are often strong protests when people are given permission to build on this land. In the US, a green belt is usually a nature area protected by a town or city. It is often a large park, with paths where people can walk. The town of Greenbelt, Maryland, was one of several created in this way in the 1930s as part of the ↑New Deal programme of President Franklin D Roosevelt
•The council rejected plans for a housing development on green belt land.