hy·po·der·mis 
(hī′pə-dûrmĭs) also hy·po·derm (hīpə-dûrm′)
(hī′pə-dûrmĭs) also hy·po·derm (hīpə-dûrm′)n.
1. An epidermal layer of cells that secretes an overlying chitinous cuticle, as in arthropods.
2. Botany A layer of cells lying immediately below the epidermis.
3. Anatomy A subcutaneous layer of loose connective tissue containing a varying number of fat cells.