Ecology and economy differ in their suffixes. Logy is from Greek logos, from legein , to gather, count, hence to recount, hence to say or speak. Logos and its Latin counterpart legere - to count, speak, gather etc. Ecology at root means the legend or logic of the dwelling place, the story of where we live. Because it embodies a changing, evolving knowing and saying I think ecology is most accurately revealed as the legend of the house.
Economy is eco plus nomos .
Nomos is from another Greek word nemein , to distribute. Economy is from Greek oikonomia , household management. Our sense of economy as thrift echoes this root sense. By extension economy has come to include all enterprise. In Greek economos meant steward, the household manager, the agent of economia, good management, thrift.