A motor vehicle service is a set of maintenance procedures carried out either at set time intervals or after the vehicle has travelled a certain distance since it's last service.
A motor vehicle service is a set of maintenance procedures carried out, usually by an appointed garage, at either set time intervals (usually 6 months or a year), or after the vehicle has travelled a certain distance since it's last service (varies by car type and model).
A motor service is not required by law, although certain standards are required, for example in the UK, the MOT Test.
A service checks several key components of a car such as:
- oil
- brake fluid
- tyres
- lights
A more complete list can be found at Wikipedia.