Confused about all the "green living" terms bandied about? Not sure of the differences between downcyling and upcyling, gray water and black water, post-consumer and pre-consumer waste? Here are some definitions of these, and more. There will be a test afterward. (Just kidding.)

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Biodegradable: By U.S. government definition, 60 to 70 percent of a product’s ingredients must be able to break down and return to the environment within 28 days.

Black water: Water containing human waste from toilets and urinals. Typically black water, after neutralization to ensure safe use, is restricted to nonpotable uses such as flushing or irrigation.

Carbon footprint: A measure of the amount of carbon dioxide emitted through the combustion of fossil fuels as part of the everyday life of an individual or the everyday operations of a business. Calculation can include waste disposal, food grown and eaten, gas to get to work, etc. Calculate yours at Web sites like See also ecological footprint at

CFL (compact fluorescent lamp): An energy-saving light bulb that is a replacement for traditional incandescent bulbs that expend much of their energy in heat rather than light.

Closed-loop recycling: Products of better-grade material made from a recycled source, such as ceiling tiles made from aluminum cans.

Compostable: Material that breaks down to become what is effectively dirt. It contains no toxins and can support plant life. Compost piles use a system: green (grass clippings, vegetable and fruit scraps, etc.), brown (dead leaves, straw, hay, wood), air and water to turn waste into growing medium.

Daylighting: Use of natural light to supplement or replace artificial lighting.

Downcycling: When products of a lower grade are made from a recycled source, such as carpet pads from tires. (Upcycling is the process of converting waste materials into something of similar or greater value in their second life.)

Eco-friendly: Little or no impact on the native ecosystem. There is no legal definition for eco-friendly.

Eco-savvy: Someone who is environmentally aware.

Ecological footprint: The area of land and water needed to produce the resources to entirely sustain a human population and absorb its waste products with prevailing technology. The concept of an ecological footprint is used as a resource management and community-planning tool.

Flat pack: Goods the end-user assembles. The unfinished product takes up less space, so more can be shipped — saving fuel and emissions. (Think Ikea’s approach to furniture.)

Gray water: Wastewater from showers, kitchens, washers, etc. Unlike black water, gray water does not contain human waste. Typically, gray water, after purification, is used for nonpotable uses such as flushing and irrigation.

Greenwashing: When more money and energy is expended on trumpeting eco-friendly practices than in making those commitments a reality. Secondarily, it’s when something is touted as green because of an ingredient, component, etc., but overall, it isn’t. For example, a cleaning product that adds a natural ingredient but still contains toxic chemicals.

Locavore: Someone who tries to eat things that were produced locally, even if it means going off the organic reservation. Usually restricted to food sources within 100 miles.

Off-grid living: Doing things without electricity or other artificial-power sources. For example, using a clothesline instead of a dryer.

Organic: Generally, organic foods use plants grown without conventional pesticides or artificial fertilizers and processed without food additives; or food products from animals that have not been subjected to routine antibiotics or growth hormones. According to the U.S. Department of Agriculture, organic foods must come from farms or ranches certified by a state or private agency that has been accredited by the USDA. Foods labeled “100 percent organic” must contain only organically produced ingredients, excluding water and salt. Foods labeled “organic” must contain, by weight, at least 95 percent organically produced ingredients.

Post-consumer recycled products: Products made with post-consumer waste, that is materials that were used by someone and then returned through a recycling program, thereby diverting them from a landfill. In contrast, pre-consumer waste is waste that has not reached its end use, for example, paper trimmings or defective aluminum cans, which are commonly used in manufacturing industries. Companies sometimes claim this as “recycling,’ but it is not in the traditional sense.

Sustainability: Can be traced back to Theodore Roosevelt, who said in 1910, “I recognize the right and duty of this generation to develop and use the natural resources of our land; but I do not recognize the right to waste them, or to rob, by wasteful use, the generations that come after us.”

Sustainable materials: Material, like certain types of wood, that have a short growth and renewal cycle (bamboo, hemp, eucalyptus), or that, when harvested, don’t degrade critical habitats. The term also is used for materials that are biodegradable, that are recyclable at the end of the usable life cycle, that reduce water or energy consumption or that help the environment.

Vampire appliances, vampire energy: Appliances that suck energy even when you’re not using them. For example, cellphone chargers, even when they’re not charging anything, the toaster when there’s no toast in it, intercom systems that are listening when you’re not talking.

— Sylvia E. King-Cohen, Newsday and Seattle Times staff