Surplus: Anysector or agent in economy (business, householdor government) experiences a surplus when its income surpasses its expenditure.
Surplus, Economic: For the economy as a whole, surplus equals the amount of production over and above what is essential for the reproduction of existing economic system (including essential consumption required to reproduce population, and depreciation on existing stock of capital). An economy's aggregate surplus can be consumed (to allow for a standard of consumption higher than mere subsistence, or to finance wasteful projects such as wars or monument-building) or re-invested to expand future production.