The ⚀uncia·lengthel, or ⚀granular·length
The first negative dozenal power of the ⚀lengthel, the ⚀uncia·lengthel (abbreviated ⚀u↓lgℓ) is a dozenth of a ⚀morsel·length. This is a fair approximation of the size of a grain of sand, or a grain of salt. As a consequence, a proposed colloquial name for this is the ⚀granular·length.