What is the meaning of economy?

noun

• The system of production and distribution and consumption.
  • synonyms: economic system
• The efficient use of resources.
  • usage: "economy of effort"
• Frugality in the expenditure of money or resources.
  • usage: "the Scots are famous for their economy"
  • synonyms: thriftiness
• An act of economizing; reduction in cost.
  • usage: "it was a small economy to walk to work every day"; "there was a saving of 50 cents"
  • synonyms: saving