lump sum 
noun
A single payment made at a particular time, as opposed to a number of smaller payments or instalments: your pension plan can provide a cash lump sum at retirement as well as a regular income [as modifier]: a lump sum payment...
- When he dies, his wife is usually guaranteed a lump sum or payment of income for five years only.
- At the end of the term, a pre-agreed single lump sum payment is made by the borrower to clear the debt.
- It stated that the funds were to be used to secure the Retirement Benefits which were an annuity and a lump sum payment.