nave height
The maximum height from floor to vaulting in the central approach to a church's altar.
The nave height of a church is the maximum height from the floor to the peak of the vaulting in the ceiling of the central approach to the altar. This does not include the height of the transept, crossing, choir, ambulatory, or side aisles. Any dome or lantern which interrupts the vaulting of the nave does not add to its height.
The measurement runs from the base of the structure, the level of the lowest significant open-air pedestrian entrance. A building on a slope therefore has one height rather than one per side, and a figure taken from the low side of the same building is a different number.
Two sources giving different heights for one building have usually measured from different levels rather than measured badly.