Food Forest: Appears to be a VERY broadly applied term encompassing a range of gardener objectives, knowledges, techniques and experiences. Bottom line: I think there can be as many definitions of Food Forest as there are gardeners trying to achieve it.
Food Foresting: …gardening technique or land management system, which mimics a woodland ecosystem by substituting edible trees, shrubs, perennials and re-seeding annuals.
— A low maintenance sustainable plant-based food production and agro-forestry system based on woodland ecosystems, incorporating fruit and nut trees, shrubs, herbs, vines and perennial vegetables which have yields directly useful to humans. Making use of companion planting, these can be intermixed to grow in a succession of layers, to build a woodland habitat.
— Forest gardening is an ancient method of securing food in tropical areas. In the 1980s, Robert Hart coined the term “forest gardening” after adapting ancient tropical principles and applying them to temperate climates. Wikipedia
— 7-Layer system adopted as a Permaculture design element. Bill Mollison
Edible Forest Gardening: …the art and science of putting plants together in woodland-like patterns that forge mutually beneficial relationships, creating a garden ecosystem that is more than the sum of its parts. Dave Jacke
Forest Garden: If you start with any part of your homestead and turn it into a more complex, polyculture, you have created a forest garden, however small the scale. Harvey Ussery