What is "carya amara"

Hickory \Hick"o*ry\, n. [North American Indian pawcohiccora (Capt. J. Smith) a kind of milk or oily liquor pressed from pounded hickory nuts. ``Pohickory'' is named in a list of Virginia trees, in 1653, and this was finally shortened to ``hickory.'' --J. H. Trumbull.] (Bot.) An American tree of the genus Carya, of which there are several species. The shagbark is the Carya alba, and has a very rough bark; it affords the hickory nut of the markets. The pignut, or brown hickory, is the Carya glabra. The swamp hickory is Carya amara, having a nut whose shell is very thin and the kernel bitter. Hickory shad. (Zo["o]l.)

1. The mattowacca, or fall herring.

2. The gizzard shad.

Bitternut \Bit"ter*nut"\, n. (Bot.) The swamp hickory ( Carya amara). Its thin-shelled nuts are bitter.