a part of a payment which is paid regularly until the total amount is paid nouna part of a payment which is paid regularly until the total amount is paid ExampleThe first instalment is payable on signature of the agreement.(NoteThe US spelling is installment.)Usagethe final instalment is now duethe last of a series of payments should be paid nowUsageto pay £25 down and monthly instalments of £20to pay a first payment of £25 and the rest in payments of £20 each monthUsageto miss an instalmentnot to pay an instalment at the right time