Please note that the business which you are carrying on, then any income generated from that business is considered as your business income. Business Income is the Total Sales that you ahve made from your business activcity less the expenditure you ahve incurred on running the business.
For instance if you carrying on the business of manufacturing shirts, then the money which you earn by selling the shirts is considered as your direct sales. Now the expenditure whihc you have incurred in manufacturing the shirts, such procuring the cloth, paying the labourers for stitching the shirts, depreciation on machinery is your expenditure incurred. The difference between the sales from shirts & expenditure incureed for these shirts, is your business income.
Hope the above would help you.