This is the amount of money left over after paying essential expenditure (such as mortgage, housekeeping etc) but before making any credit repayments. If this is a negative amount, it is known as a deficit.
Payment required, if any, to be made by a bankrupt to the estate for distribution to creditors. The amount of the payment is fixed by the trustee, having regard to the standards established by the Superintendent and to the personal and family situation of the bankrupt.
Every year, the Superintendent of Bankruptcy publishes guidelines outlining how much money a bankrupt person is allowed to keep to pay for their own personal expenses. Any money that a bankrupt person earns above the amounts set out in the guidelines is called "surplus income".