Income is the money that someone gets for business activities. For individuals income usually means their wages or salary before any tax and other deductions have been made by their employer. Overall it is the amount you earn after all outstanding deductions have been made. Gross income is the income from all sources including wages or salary.
For business, there is a difference between the USA, where it most often means the amount of money that a company earns after paying for all its costs, and the world outside the U.S., where the term is usually profit or earnings.