One of the mysteries of the English language finally explained.
A dark-coloured solution of soap and impurities (colouring material, alkali, etc.) which settles out from the pure soap during the final stage of the manufacturing process.
Mid 19th century; earliest use found in Andrew Ure (1778–1857), chemist. Apparently from classical Latin nigr-, niger black.
In this article we explore how to impress employers with a spot-on CV.