Lewis Short
nīgrēdo (noun F) : niger
* Blackness, black color (post-class.): capilli corvinā nigredine,App. M. 2, p. 118, 31: nigredo ollae,Vulg. Nah. 2, 10; Mart. Cap. 2, § 137: atrae noctis,id. 1, § 67.
Charlton T. Lewis, Charles Short, A Latin Dictionary