WordReference Random House Unabridged Dictionary of American English © 2026
ep•i•trich•i•um
(ep′i trik′ē əm),USA pronunciation n., pl. -ums. [Embryol.]
ep′i•trich′i•al, adj.
- Developmental Biologythe outermost layer of the epidermis in most mammalian fetuses, usually disappearing before birth. Also called periderm.
- Greek tríchion, diminutive of thríx hair (see trichion); so called because hair develops under it in human embryos
- Neo-Latin epi- + -trichium
- 1880–85
'epitrichium' also found in these entries (note: many are not synonyms or translations):