Lewis & Short

tĕnē̆bresco (tĕnē̆brasco), ĕre, v. inch. n. [tenebrae], to grow or become dark (eccl. Lat.), Hier. in Isa. 5, 12, 10; Aug. Genes. ad Lit. 1, 10 fin.; Vulg. Amos, 8, 9: oculus, id. Zach. 11, 17.