What term describes the portion of a building between the uppermost surface of any floor and the uppermost surface of the next floor?

The term that describes the portion of a building between the uppermost surface of any floor and the uppermost surface of the next floor is "storey." A storey is a unit of measurement that refers specifically to the vertical space between two floors, encompassing both the floor itself and the space above it until the next floor starts.

This definition is crucial in architecture and building regulations, as it helps determine the total height of a building, the number of floors, and can influence zoning laws and building codes.

The other options—room, space, and level—do not accurately define this architectural term. A room refers to an enclosed area within a building, while level refers more generally to a horizontal plane or position, which does not specifically denote the relationship between two floors. Space lacks the specificity necessary in construction terminology to describe the area between floors accurately. Thus, "storey" is the correct choice.