Organic non-fossil material of biological origin that is a byproduct or a discarded product.

Biomass waste includes municipal solid waste from biogenic sources, landfill gas, sludge waste, agricultural crop byproducts, straw, and other biomass solids, liquids, and gases; but it excludes wood and wood-derived fuels (including black liquor), biofuels feedstock, biodiesel, and fuel ethanol.

It should be noted that some so-called biomass waste also includes energy crops grown specifically for energy production, which would not normally be considered waste.