eponychium

plural ep·o·nych·i·a [ep-uh-nik-ee-uh], /ˌɛp əˈnɪk i ə/,

• : Embryology. the modified outer layer of the epidermis that partially covers the fetal fingernails and toenails and that persists after birth as the cuticle.
• : Anatomy. a thin, cuticular fold extending over the lunula of a nail.