* Ivory is the name commercially given not only to the substance constituting the tusks of the elephant, but also to that of the tusks of the hippopotamus and walrus, the hornlike tusk of the narwhal, etc.

Ivory black. See under Black, n. -- Ivory gull (Zoöl.), a white Arctic gull (Larus eburneus). -- Ivory nut (Bot.), the nut of a species of palm, the Phytephas macroarpa, often as large as a hen's egg. When young the seed contains a fluid, which gradually hardness into a whitish, close-grained, albuminous substance, resembling the finest ivory in texture and color, whence it is called vegetable ivory. It is wrought into various articles, as buttons, chessmen, etc. The palm is found in New Grenada. A smaller kind is the fruit of the Phytephas microarpa. The nuts are known in commerce as Corosso nuts. -- Ivory palm (Bot.), the palm tree which produces ivory nuts. -- Ivory shell (Zoöl.), any species of Eburna, a genus of marine gastropod shells, having a smooth surface, usually white with red or brown spots. -- Vegetable ivory, the meat of the ivory nut. See Ivory nut (above).