mesencephalon

synonym: midbrain
https://doi.org/10.1351/goldbook.10940

Part of the vertebrate brain that develops from the middle section of the embryonic neural tube.

Source:
PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 777 [Terms] [Paper]