A mismatch in the net expected revenue and actual revenue receipt for the government can result in revenue deficit. If the actual revenue receipt is higher than the expected revenue receipt, then it will be called revenue surplus and it will be positive for the economy. One should note that revenue deficit does not result in revenue loss. Let us understand with an example

If the governments expected revenue receipt in financial year was Rs 1 lakh crore but they actually received Rs 90000 crore only, then it will be termed as revenue deficit of Rs 10000 crore. This does not mean that Rs 10000 crore was actual loss to the government, but it was less than what was expected at start of the year.