eponychium
noun
ep·o·nych·i·um
| \ ˌep-ə-ˈnik-ē-əm
\
\
Medical Definition of eponychium
1
: the thickened layer of epidermal tissue over the developing fetal fingernail or toenail that disappears before birth except over the base of the nail
2
: the distal margin of the superficial layer of a proximal nail fold that is a horny band of epidermis extending over the base of a nail : cuticle