Armrest

In an automotive context, an armrest (or arm rest) is a feature found in many modern vehicles on which occupants can rest their arms. Armrests are also found on chairs in general.
Armrests are more prolific in larger, more expensive models of cars.
Front.
In the front of the car, a central armrest, which commonly folds away based on user preference, will also often include a storage compartment and sometimes even cup holders. Some also provide the location for controls for non-essential functions of the vehicle, such as climate control or window motors.
Sometimes one or two armrests may also be attached to each individual seat, a feature commonly found in minivans (MPVs) and some SUVs.
Frequently there is a further armrest built into the door of the car, often forming part of the door pulling handle.
Rear.
A rear arm-rest will typically fold away between the back seats, to allow for the central (third) seating place to be used. In some designs where occupant safety is emphasised, including some Volvo models, the armrest doubles as a child seat, complete with specially adjustable seatbelt. As with the front, it is not unusual to have armrests built into rear doors, or the side of the car if there is no rear door.