"Carbon neutral" may have been the New Oxford American Dictionary's 2006 word of the year, but it was only recently added to the Shorter Oxford English Dictionary (which is, presumably, a shorter, British-er version of the same tome?). The SOED defines "carbon neutral" as "making no net release of carbon dioxide to the atmosphere, especially through offsetting emissions by planting trees."

Other green buzzwords that made the cut:

• green audit: "an assessment of a business as regards its observance of practices which seek to minimise harm to the environment"
• carbon footprint: "the amount of carbon dioxide emitted due to the activities, especially the consumption of fossil fuels, of a particular person, group, etc"
• carbon trading: "emissions trading -- a system whereby countries and organisations are given permits to produce a particular amount of carbon dioxide and other greenhouse gases, which they may trade with others"

In semirelated news, the hyphen is quickly becoming an endangered species ...