Quite simply, a house, villa, condo, apartment or townhouse legally rentable for short-term self-catering holidays. We say “legally” because some areas have ordinances prohibiting short term rental properties, (even in the same development!), so you would not want to buy there - but it has been known......
The properties are usually three to six bedroom, fully furnished, with a private patio and heated pool. But condominium apartments, (flats), are also popular with smaller parties, or people with lower budgets. Visit a sample here
Most people employ a management company to look after their short-term-rental investment. NWRE has a company which not only does this, but also actively seeks bookings for our owners. See finding renters.