How Good is Your Green Vocab?

Your carbon footprint is the quantity of greenhouse gas created by supporting your lifestyle-your clothes, food, home, buying habits, travel plans, and so on. Calculate yours with The Nature Conservancy's carbon footprint calculator.

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Your Carbon Footprint: Calculating, Reducing, and Offsetting Your Impact Calculate Your Ecological Footprint
Pledge to Reduce Your Carbon Footprint

Each of these is a product service system, or PSS, which lets consumers share resources by renting, borrowing from, or—in the case of the cat cafe—just visiting a store instead of contributing to consumption by buying their own products. Product service systems aren't as far-out as they sound: Your good ol' local library is also a type of PSS!

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What Makes a Good Product Service System?
PSS Handbags: Bag, Borrow, or Steal
EcoTip: Product Service Systems (PPS)

Even when you aren't using your electronics, many are still drawing power—think of those little lights on your TV, the clocks on your DVR and microwave, and the phone charger that you keep plugged in even when your phone isn't. Unplugging all your electronics from the wall when you aren't using them can save you as much as 10 percent on your energy bill.

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Green Glossary: Vampire Power
Save Energy by Avoiding Phantom Power
Another Stake Through the Heart of Vampire Power

Planet Green's Mickey Z quoted this definition in his post on photovoltaics: it's "the field of technology and research related to the application of solar cells for energy by converting sunlight directly into electricity." Since the U.S. Department of Energy has claimed it has all the positives we listed in answer 2, this is a term you're sure to be hearing a lot in the future.

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Green Glossary: Photovoltaics
Let's Go Solar
15 Photovoltaics Solar Power Innovations You Must See

At the Daylighting Collaborative, they define daylighting as "the practice of using natural light to illuminate building spaces...[r]ather than relying solely on electric lighting during the day." Though it may mean your windows are placed according to the sun's path instead of traditional aesthetics, the energy savings are worth it.

Read more:
Green Lighting: Getting Techie
Green Glossary: Daylighting
DayRay: Flexible Daylighting

Grey water is water you've salvaged after using it for something else—washing the dishes, maybe, or from taking a shower or brushing your teeth. It's a great way to save water on your household needs without wasting fresh (you just don't want to drink it or cook with it).

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Green Glossary: Grey Water
Grey Water Guerrillas
Reuse Your Grey Water with the Take-Away Sink

While clean coal is intended as a label for technologies that burn coal while creating less pollution, there is no such thing as 100% clean coal; no matter how your burn it, the same amount of carbon is released. Many environmentalists consider the term "clean coal" to be an oxymoron.

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Green Glossary: Clean Coal
There is No Such Thing as Clean Coal
Wind Power Beats Nuclear & Clean Coal, Other Renewables as US's Best Energy Option

Precycling happens when you buy an item and make a choice that means less packaging waste—whether that means choosing the bulk cereal instead of the individually-wrapped single-serving boxes or picking up a reusable tote to carry to the grocery store.

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Jargon Watch: Precycling
7 Overrated Technologies and Their Underrated Low-Tech Counterparts

Hypermiling includes a variety of actions that help you get the best gas mileage, from driving the speed limit and keeping your tires properly inflated to braking and accelerating gently and taking off the roof rack when you're not using it.

Read more:
Hypermiling Becoming More Popular as Gas Prices Rise
Six Amazing Hypermiling Videos
Micro-Hypermiling: Saving Gas Where You Drive the Most

Turning land that was never—or at least not recently—forest into a plot of trees is afforestation. It's been done in Europe on farmlands and in India on 15 million acres. Reforestation is the act of reviving an existing but dying or decimated forest.

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Green Glossary: Afforestation
India Announces New Climate Change Strategy