Alcohol - Any organic compound that contains an oxygen single-bonded to a hydrogen atom (OH group).

Algae - A group of diverse, generally autotrophic organisms that can be either single-cell or multi-cell. Various species of algae are used to produce ethanol and butanol.

Biobutanol - Butanol produced from biomass. It can be used in unmodified gasoline engines.

Biodiesel - Diesel fuel produced from biomass. Biodiesel cannot be used in standard engines without modification as it corrodes rubber seals and gaskets. It also has a lower gelling point than petrodiesel, making it unsuitable for use in colder climates. Biodiesel is often blended with petrodiesel.

Biodiversity - The amount of variation in an ecosystem. Greater variation indicates a healthier ecosystem. Genetically modified organisms and large monocultures used in biofuel production can threaten biodiversity.

Bioenergy - Any renewable energy made from biological sources. Fossil fuels are not counted because, even though they were once biological, they are long dead and have undergone extensive modification.

Biofuel - Any fuel derived from biological carbon fixation, including solid fuels, bioethanol and other bioalcohols, biodiesel, etc.

Biogas - A mixture of methane and CO2 with water vapor created by the breakdown of organic matter in the presence of oxygen.

Ethanol - An alcohol composed of two carbons.

Fermentation - A normal metabolic process in which oxygen is NOT the final electron acceptor. Fermentation is the process through which alcohols are made.

Fossil fuel - A fuel formed by the anaerobic decomposition, over thousands or millions of years, of dead biomass. Petroleum, coal, and natural gas are major categories of fossil fuels.

Greenhouse Effect - The warming of the Earth as a result of heat that is trapped by certain gases.

Jatropha - A genus of flowering plants that grown in tropic regions, on marginal land. Oil from Jatropha seeds can be used to produce biodiesel.

Photosynthesis - The process by which living organisms like plants and algae convert light energy into chemical energy.

Triglyceride - Organic compounds composed of three fatty acid chains connected to a glycerol molecule.