Deficit is the amount by which expenses exceed income or costs outstrip revenues. Deficit essentially refers to the difference between cash inflows and outflows.
Primary deficit is the gross deficit which is obtained by subtracting interest payments from budget deficit of any country of a particular year. It corresponds to the net borrowing, which is required to meet the expenditure excluding the interest payment.
Budget deficit is when a country’s government spends more than it takes in from taxes or other forms of revenue.
Revenue deficit occurs when the net amount received (revenues less expenditures) falls short of the projected net amount to be received. When a country runs a revenue deficit it means that the government is unable to meet its running expenses from its recurring income.