Past tense of 'green'; made green or covered with vegetation, or adopted environmentally friendly practices.
From green (verb) + -ed (past tense marker). The verb 'to green' developed modern usage especially from the 1970s onward as environmental consciousness grew and 'greening' initiatives became common.
The term 'greened' exploded in the 1990s-2000s when companies started 'greenwashing'—making themselves appear environmentally friendly through marketing while not always making real changes, leading to the coining of a very useful skeptical term!
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