Airbnb is a concept that has only been around for a few years, but it has exploded around the globe. Airbnb allows people to travel all around the world and to stay in accommodations that are a lot less expensive than traditional hotels. They do this by staying with participating Airbnb members who rent out part of their homes to travelers. By participating in Airbnb, you can use your residence to accommodate guests and earn extra money just for renting out space in your home.
For a person working for a wage, their source of income is their job, or their labor (aka their time that they sell to someone). But you can own a house, and rent it out, and when your renters pay you renter every month, the source of that income check is your rental property, or your house. It would just be called rental income. If you have money in the bank in an account that pays interest, those interest payments are another source of income. We can say the source is interest payments, or we can identify the asset that is generating rent, and say your money in the bank that is generating “rent” (aka interest) is your source of income.