Today is Earth Day, the annual celebration launched 41 years ago to raise environmental awareness. What better time to get up to speed with the latest in "green" lingo? Here are ten eco-friendly words that have gained prominence over the last few years.

Anthropocene: This term refers to the current geological era, characterized by the (often adverse) impact that humans have had on the environment. Nobel Prize-winning atmospheric chemist Paul Crutzen first proposed the term in 2000. Others had previously hit upon similar ideas: Andrew Revkin coined anthrocene for a 1992 book on global warming, but Crutzen's version (using the full Greek combining form anthropo- for "human") was the one that caught on among geologists. A scholarly paper last year, "The New World of the Anthropocene," made a strong case for branding the current era (roughly since the Industrial Revolution) with Crutzen's term. In his recent book Virtual Words, Jonathon Keats argues that Anthropocene "was meant to serve as a call to action, not just a physical observation." Crutzen had previously combined science with activism when he helped to popularize the concept of nuclear winter.

bright green: Everybody knows that green has become synonymous with the environmental movement. But do you know about its different shades? In 2003, the writer Alex Steffen proposed three gradations. Bright green environmentalism holds that "sustainable innovation is the best path to lasting prosperity." "In short, it's the belief that for the future to be green, it must also be bright," Steffen has written. He contrasts the bright greens with the light greens (those who see environmentalism as a lifestyle choice) and the dark greens (those who want to pull back from consumer capitalism). And if you think the environment is just fine as it is? Then you're a gray.

(Speaking of environmental color-coding, the whole green thing has become a bit clich├ęd. As Nancy Friedman suggested in a Candlepower column two years ago, companies seeking to project themselves as eco-conscious might be better off using the color blue in their names, suggesting clear skies and waters.)

carbon shredder: In environmental circles, carbon has become a kind of shorthand for the emission of carbon dioxide and other greenhouse gases into the atmosphere. Back in 2007, I surveyed various carbon compounds that had sprung up, like carbon-neutral, carbon calculator, carbon footprint, carbon credits, and carbon taxes. Later that year, another compound was coined: carbon shredder, for someone who works assiduously to reduce carbon-dioxide emissions. The first self-designated carbon shredders were three activists in the Mad River Valley region of Vermont who sought to encourage local towns and businesses to curtail their carbon footprints. Shredder is an evocative term, as long as you don't think too hard about how you'd go about "shredding" atmospheric gases.

eco-dentistry: The prefix eco- is an old standby for environmentalists, and it continues to spawn new words. One such eco-term that has emerged in the past few years is eco-dentistry (also called green dentistry), promoting environmentally sound practices of professional dental care. There's even an Eco-Dentistry Association that has launched internationally to help dentists and their patients make eco-friendly choices. (Oddly, Lindsay Lohan's mother Dina has tried to get in on the eco-dentistry act by introducing a "green toothbrush" that doesn't use water.)

geoengineering: Scientists looking for radical solutions to counteract global warming have come up with rather startling proposals to manipulate the Earth's climate. Such climate-hacking, or geoengineering, includes everything from the creation of giant "space sunshades" for the planet to the seeding of cirrus clouds. And then there's the Pinatubo option, which would mimic the effect of a big volcanic eruption (like Mount Pinatubo in the Philippines) by injecting reflective particles into the stratosphere as a way of cooling the planet. Sounds a bit off the charts, but it's receiving serious consideration from climate scientists.

locapour: You might have heard about locavores, those who seek to consume only locally grown food (where "local" is defined by a radius of, say, 100 miles). The locavore movement began in San Francisco in 2005, and two years later it was prominent enough that it was named the New Oxford American Dictionary Word of the Year. I was editor for American dictionaries at Oxford at the time, so it fell to me to make the announcement: "The word locavore shows how food-lovers can enjoy what they eat while still appreciating the impact they have on the environment." Locavorism has gained more steam since then, and has even given rise to the locapour offshoot, for those whose wine and beer consumption is limited to locally produced brands.

plantarian: While locavore uses the -vore suffix of carnivore and herbivore, the -tarian suffix has proved even more productive for naming new classes of eaters. Starting with vegetarians in the 19th century, there have been fruitarians (fruit eaters), nutarians (nut eaters), pescetarians (fish eaters), and flexitarians (flexible vegetarians). Now there are plantarians, who promote a plant-based diet as a healthy lifestyle choice. The Plantarian website says that the movement "takes the healthiest bits of vegetarian and vegan to form a diet that promotes optimum health and sustainability."

precycling: Some argue that the most effective way to reduce the detritus of consumer culture isn't by recycling but by precycling. That means avoiding those items that generate waste in the first place, like packaging materials or bottles and cans. One new initiative from a company called SodaStream seeks to reduce the number of soda bottles and cans that end up in landfills by introducing a home soda maker, "just in time for Earth Day." You can think of precycling as something like the prehab that Charlie Sheen has engaged in as a way of avoiding future rehab. (But let's hope the results are more effective than Mr. Sheen's.)

solastalgia: This word, coined by the environmental philosopher Glenn Albrecht in 2004, combines Latin solacium ("comfort") with Greek -algia ("pain") to describe a feeling of despair when one's home environment changes. Albrecht had witnessed the changes to the Upper Hunter Region of New South Wales, Australia wrought by coal mining, and observed that the emotions of the residents were similar to displaced populations, even though they weren't displaced. He came up with solastalgia to capture "a form of homesickness one gets when one is still at 'home.'" Albrecht's poignant neologism has struck a chord, and it has spread widely in the past several years.

warmist: Among those skeptical that human practices are responsible for global warming, the term warmist has caught on to describe those on the other side of the ideological divide. But Paul McFedries of Wordspy points out that it was originally a neutral label, as used in a 1989 column by Howard Rheingold: "Those who accept the global-warming theory are said to take the warmist position." Conversely, scientists who warned of a coming Ice Age could be called coldists. But as arguments over global warming became more polarized, warmist turned into a pejorative, especially popular among conservative pundits during the "Climategate" controversy. Overall, though, warm has cooled: environmentalists have increasingly shied away from the term global warming, preferring instead to talk of climate change.