What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
Any of certain typically black or dark-coloured substances made by chemical means; a dark residue or precipitate; especially = ethiops mineral.
Late 17th century; earliest use found in John Pechey (d. 1718). From classical Latin Aethiops inhabitant of Ethiopia, in post-classical Latin also denoting a black substance.