Definition of green belt:
(n) :
(urban studies) (chiefly British) An area of agricultural land around an urban area that is protected from large-scale building.
(n) :
A strip of land with plants in a place which is otherwise bare.
(n) :
Senses relating to an area of land with plants on it.
(n) :
(urban studies) A strip of land next to a building, open space, road, etc., with plants on it, intended for exercise or recreation.
(n) :
(martial arts) A belt which is green in colour worn by a person who has achieved a certain (usually intermediate) level of skill in a martial art, especially judo or karate; also, the level of skill represented by this belt.
(n) :
(martial arts) A person who has earned the rank of green belt in a martial art.