Real Dictionary

green revolution
singular noun: The green revolution is the increase in agricultural production that has been made possible by the use of new types of crops and new farming methods, especially in developing countries.

green revolution in American English
the simultaneous development of new varieties of food plants and improved agricultural techniques, resulting in greatly increased crop yields
noun: an increase in food production, esp. in underdeveloped and developing nations, through the introduction of high-yield crop varieties and application of modern agricultural techniques

green revolution in British English
noun: the introduction of high-yielding seeds and modern agricultural techniques in developing countries