What is Zero Waste? In the words of the Zero Waste International Alliance:
Zero Waste is a goal that is ethical, economical, efficient and visionary, to guide people in changing their lifestyles and practices to emulate sustainable natural cycles, where all discarded materials are designed to become resources for others to use.
Zero Waste means designing and managing products and processes to systematically avoid and eliminate the volume and toxicity of waste and materials, conserve and recover all resources, and not burn or bury them.
Implementing Zero Waste will eliminate all discharges to land, water or air that are a threat to planetary, human, animal or plant health.
Or to let Bea Johnson explain it, just watch the video below.