An Airbnb is a short-term rental, typically used by people on vacations in place of a hotel or motel room. Although it's actually a brand name, Airbnb has become commonly used to describe any type of short term rental, including Vrbo, another really popular platform. People might rent something on Vrbo and still refer to it as an Airbnb, much like some people call all sodas "Coke" or all bandages "Band-Aids." An apartment is something you rent to actually live in. Usually there's a minimum lease of 6 months or a year when you rent an apartment, although some landlords provide a month-to-month option. If you want to leave any sooner, you might have to break a lease. (Here's an article about how to break a lease.) You would probably only rent an apartment instead of an Airbnb if you were planning on staying at least a month, and probably longer than that.