Sum paid once a month in exchange for work.

The date on which a debt becomes due for payment. (source: investorwords.com )

A single payment made at a particular time, as opposed to a number of smaller payments or instalments. (source: http://www.oxforddictionaries.com/definition/english/lump-sum)

A debt that will be paid back at some point in the future with no penalty fees or interest charges assessed.

The amount which is paid each month for a deferred purchase, a loan, a service, or a bill.

The situation where an entity cannot raise enough cash to meet its obligations, or to pay debts as they become due for payment. (source: http://www.businessdictionary.com/definition/insolvency.html#ixzz2Mr8zrRJO)

definición en inglés: the state of being in financial difficulties. (source: http://www.thefreedictionary.com/indebtedness)

A time past the deadline for an obligation during which a late penalty that would have been imposed is waived. (source: http://en.wikipedia.org/wiki/Grace_period)

The whole, regarded as the complete sum of a number of parts.

A debt is discharged in full