What do you call a facility that has multiple floors of parking under one roof?

The term "multi-storey car park" accurately describes a facility that has multiple floors of parking under one roof. This type of structure is specifically designed to maximize space and accommodate a large number of vehicles in an urban setting where ground space might be limited. By building upwards instead of outwards, these facilities can efficiently serve the parking needs of a bustling area, providing easy access for drivers on several levels.

In contrast, a parking garage may refer to a similar facility but can sometimes denote a more general shelter for parking without emphasizing the multi-level aspect. A parking lot typically refers to an open area designated for parking vehicles at ground level, lacking any vertical structure. Surface parking also indicates parking on a flat outdoor area without any multi-level facilities involved. Therefore, the term "multi-storey car park" best encapsulates the concept of having several floors dedicated to parking beneath one exterior structure.