In soapmaking, the lower layer of liquid produced by pitching, which contains most of the impurities.

plural of nigre

The process of becoming black or dark; blackening. / A dark complexion.

Approaching blackness; blackish, dark-coloured.

(alchemy) A process of putrefaction or decomposition, one of the four major stages of the alchemical magnum opus. / (psychology) A term in Jungian psychology referring to mental negativity.

plural of nigress

Synonym of niggeress

plural of nigrescence

(organic chemistry) A cardenolide found in Parquetina nigrescens.