Real Dictionary

economy
countable noun: A country's economy is the wealth that it gets from business and industry.
countable noun: An economy is the system according to which the money, industry, and trade of a country or region are organized.

economy in American English
the management of the income, expenditures, etc. of a household, business, community, or government
adjective: intended to save money
adverb: in economy-class accommodations, or by economy-class conveyance
noun: thrifty management; frugality in the expenditure or consumption of money, materials, etc.

economy in British English
noun: careful management of resources to avoid unnecessary expenditure or waste; thrift