She wants to restore an old theater that is 'falling into decay'. [=falling into ruin]
We're concerned about the 'decay' [='deterioration'] of our public school system.
Tomatoes that fall off the vine will 'decay' [='rot'] on the ground.
(..) so the deciduous forests of America begin to shut down losing their leaves in preparation for the dark cold months ahead. One season hands over to another. Some organisms thrive on decay, but most must make special preparations for winter and a life with little sun. Whole populations of animals (..)2006 TvShow: Planet Earth Title: From Pole to Pole Season: 1 Episode 1