Definition of nigre in US English:

nigre

(also niger)

noun

Soap-making
  • 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.

Origin

Mid 19th century; earliest use found in Andrew Ure (1778–1857), chemist. Apparently from classical Latin nigr-, niger black.

Pronunciation

nigre

/ˈnʌɪɡə/