A land-use system in which woody perennials (trees, shrubs, palms, bamboos) are deliberately used on the same land management unit as agricultural crops (woody or not), animals or both, either in some form of spatial arrangement or temporal sequence. In agroforestry systems there are both ecological and economic interactions between the different components.
World Agroforestry Centre, 1997

The practice of planting trees on agricultural farms, especially on peripheral bunds of fields, for simultaneous production of food crops and trees. As a production system, agroforestry is superior to pure cropping. Trees, apart from bringing up nutrients from the deeper layers of soil, provide shelter, maintain temperature modernization and humidity in the atmosphere, improve the organic content of the topsoil, and promote fertility enhancing soil-fungi such as the root associative mycorrhizae and the nitrogen fixing rhizobia.
Siyag, P.R., 1998

An agro-forest is a complex of tree areas within an area that is broadly characterised as agricultural or as an agro-ecosystem.
UNEP/CBD/SBSTTA, 2001

A complex of tree areas within an area that is broadly characterized as agricultural or as an agro-ecosystem
ITTO, 2002

Land management which combines agricultural crops with tree crops and forest plants and/or animals simultaneously or sequentially and applies management practices which are compatible with the cultural pattern of the local population.
PEENRA website