What is the name of the thin clear sub-layer of the epidermis?

The thin, clear sub-layer of the epidermis is known as the Stratum Lucidum. This layer is primarily found in areas of thick skin, such as the palms of the hands and the soles of the feet. The Stratum Lucidum consists of several layers of dead keratinocytes that provide an additional barrier and contribute to the skin's durability and strength against friction and shear stress.

In contrast, other layers of the epidermis have different characteristics: the Stratum Granulosum contains granules that are involved in the process of keratinization, the Stratum Spinosum is characterized by spine-like projections of keratinocytes that provide structural support, and the Stratum Corneum is the outermost layer composed of fully keratinized, dead skin cells that serve as a protective barrier against environmental damage and water loss. Therefore, the Stratum Lucidum's clear and thin nature makes it distinct within the epidermal layers, aligning with the definition provided in the question.