corium

Short definition from Wiktionary

Noun

1. 1
   The layer of skin between the epidermis and the subcutaneous tissues; the dermis.
2. 2
   The deep layer of mucous membranes beneath the epithelium.
3. 3
   Armour made of leather, particularly that used by the Romans.
4. 4
   A lavalike mixture of fissile material created in a nuclear reactor's core during a nuclear meltdown.