mid-13c. (late 12c. as a surname), Anglo-French ivorie, from Old North French ivurie (12c.), from Medieval Latin eborium "ivory," noun use of neuter of Latin eboreus "of ivory," from ebur (genitive eboris) "ivory," probably via Phoenician from an African source (compare Egyptian ab "elephant," Coptic ebu "ivory").
It replaced Old English elpendban, literally "elephant bone." Applied in slang to articles made from it, such as dice (1830) and piano keys (1818). As a color, especially in reference to human skin, it is attested from 1580s. Ivories as slang for "teeth" dates from 1782. Black ivory was ivory burnt and powdered, used as a pigment (1810); the sense "African slaves as an article of commerce" is attested from 1834.
Mr. Dunlap then asked the witness what he himself traded in, when on the African coast, and he replied "sometimes in black ivory;" but, being more closely pressed to explain what he meant by "black ivory," he admitted that when he could not get a cargo of real ivory, he took one of slaves. ["Trial of the Twelve Spanish Pirates," Boston, 1834]
Related: Ivoried; ivorine.