Gross income is the total amount earned before anything is taken out, while net income is what is left after taxes, deductions and expenses are subtracted. For an employee, gross income is the full salary or wages on the pay stub, and net income is the take-home pay after income taxes, payroll taxes and contributions such as a 401(k) or Health Savings Account are withheld.
For a business, net income is the “bottom line” of the income statement: total revenue minus all operating costs, cost of goods sold, interest and taxes. Net income is also not the same as adjusted gross income (AGI) on a US tax return, because AGI is calculated before standard or itemized deductions and before tax is subtracted.
Source: Investopedia: Net Income (NI) definition and calculation
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