A secondary use is any intended function which occupies 10% or less of a place's gross floor area or ground area. Parking is considered a secondary use when it occupies less than 50% of the gross area.

The percentage concerns the area devoted to the intended function. A small floor-area share can make an activity secondary even when that activity has a separate name or operator.

The stated 10% limit meets the lower limit in primary use; the existing definitions share that boundary value. Parking has its own 50% condition, so the general 10% test does not determine its secondary status.