What is the name and function of the thickest layer of cells next to the epidermis?

The thickest layer of cells next to the epidermis is called the stratum corneum. Its primary function is to provide a protective barrier against environmental hazards, such as pathogens and physical abrasions, while also preventing water loss from the underlying layers of skin. This layer consists of dead, flattened keratinocytes that are continuously shed and replaced.