substantia nigra
/səbˈstanʃə ˈnʌɪɡrə/Anatomy
noun
A large nucleus of the midbrain that contains (especially in adult humans) a layer of dark melanin-laden cells, and is a part of the extrapyramidal motor system which is involved in Parkinson's disease and certain other disorders of movement.
Origin
Early 19th century. From scientific Latin substantia nigra, lit. black substance from classical Latin substantia + nigra, feminine of niger black.