The short answer today is “who knows”?
The amendments of 2005 did not define the term. We know that the definition does not confine itself to taxable income. We know that Social Security benefits are not income.
There is a logical argument that cash that results from turning an asset into cash, such as the sale of a house, or a loan is not income.
These issues remain for courts to decide, along with many other changes made to the Bankruptcy Code.