Floor pan refers to the base of a vehicle's interior where the driver and passengers stand or sit. Some synonyms for floor pan include "chassis," "undercarriage," "bottom frame," "floorboard," and "subfloor." These terms are commonly used in the automotive industry and are often used interchangeably with floor pan. In addition, depending on the context, related terms such as "footwell" and "cabin floor" might also be used to refer to the same area. Understanding these synonyms can help when communicating with mechanics or researching vehicle parts, as well as providing a better overall understanding of a car's construction and function.