Business income is the total of revenue earned PRIOR to deducting your business expenses.
Business Income - Business Expenses = Net Income
In Turbo Tax, you'd enter your total income and then your total expenses. The program will then calculate the Net Income for you.
You operate at a "profit" when your total business income exceeds your total business expenses. Conversely, you operate at a "loss" when your total business expenses exceed your total business income.