ectoderm

https://doi.org/10.1351/goldbook.10632

In an embryo, outermost layer that develops into the epidermis of the skin and the nervous system.

Source:
PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 746 [Terms] [Paper]