A government budget is a projection of the government's revenues and expenditure for a particular period of time often referred to as a financial or fiscal year, which may or may not correspond with the calendar year. Government revenues mostly include taxes while expenditures consist of government spending. A government budget is prepared by the government or other political entity. In most parliamentary systems, the budget is presented to the legislature and often requires approval of the legislature. Through this budget, the government implements economic policy and realizes its program priorities. Once the budget is approved, the use of funds from individual chapters is in the hands of government ministries and other institutions. Revenues of the state budget consist mainly of taxes, customs duties, fees and other revenues. State budget expenditures cover the activities of the state, which are either given by law or the constitution. The budget in itself does not appropriate funds for government programs, hence need for additional legislative measures. The word budget comes from the Old French bougette.