Passive income

Passive income is income resulting from cash flow received on a regular basis, requiring minimal to no effort by the recipient to maintain it.

The U.S. Internal Revenue Service categorizes income into three broad types, active income, passive income, and portfolio income. It defines passive income as only coming from two sources: rental activity or "trade or business activities in which you do not materially participate." Other financial and government institutions also recognize it as an income obtained as a result of capital growth or in relation to negative gearing. Passive income is usually taxable.

Some examples of passive income are:

The U.S. IRS has a specific definition of passive income that excludes some of the incomes listed above. Royalties for example, are, according to the Service guide, generally non-passive in nature. Additionally, interest, dividends, annuities, and gains from stocks and bonds, lottery winnings, salaries, wages, commissions, retirement income, guaranteed payments for services are considered by the IRS to be non-passive.

...
Wikipedia