Enter a clue or pattern or both:
The Clue
Embryological layers (9 letter answer)
The Answer
ECTODERMS
Tags
Notes
The answer ECTODERMS is so rare that it appears less than once every 2500 puzzles.
Definition
ECTODERM as a noun:
1. (ectoderm, exoderm, ectoblast) = the outer germ layer that develops into skin and nervous tissue