What is the name of the outermost layer of human skin?

The outermost layer of human skin is the epidermis.

The epidermis is a thin, multilayered sheet of epithelial tissue that forms the body’s first barrier against pathogens, chemicals, and water loss. Its main cells are keratinocytes, which produce keratin, a tough protein that helps protect the surface.

New cells form in the deepest epidermal layer, the stratum basale, then gradually move upward. As they mature, they become flatter, fill with keratin, lose their nuclei, and eventually form the stratum corneum—the epidermis’s outermost sublayer. These dead surface cells are continuously shed and replaced.

The epidermis is often confused with the dermis, which lies beneath it and contains blood vessels, nerves, glands, and hair follicles. The hypodermis or subcutis is deeper still and is largely made of connective and fatty tissue. Unlike the dermis, the epidermis itself has no blood vessels; it receives nutrients by diffusion from tissues below.