What is meant by ( net income ) ?

In business, net income is gross income minus expenses. Personally, gross income is the amount you earn before taxes and other payroll deductions. Net income is your take-home pay after taxes and other payroll deductions. Your net income is the amount on your paycheck.

For self-employed taxpayers net income is what is left after deducting business expenses, materials, wages paid to employees, etc.   It is what is left that is taxable income - i.e. your profit from the business.