A limousine is a large luxury vehicle typically driven by a chauffeur often with a partition between the driver’s compartment and the passenger’s compartment.
A large and fancy car with a partition as well as greatly longer than standard and that is driven by a professional driver is described as a “stretch limo”.
In some countries like USA, Germany, Canada, a “limousine service” is a pre-booked hire car with driver, regardless of the type of vehicle. It also describes a large vehicle for transporting passengers to and from an airport.
In German-speaking countries, a Limousine is simply a full-size sedan, while a lengthened-wheelbase car is called Stretch-Limousine.