WordReference Random House Unabridged Dictionary of American English © 2026
pro•to•derm
(prō′tə dûrm′),USA pronunciation n. [Bot.]
- Plant Biologya thin outer layer of the meristem in embryos and growing points of roots and stems, which gives rise to the epidermis. Also called dermatogen.
- proto- + -derm 1930–35
'protoderm' also found in these entries (note: many are not synonyms or translations):