Emily Dickinson Lexicon

POR'PESS, n. [It. porco, a hog, and pesce, fish; hog-fish, called by other nations, sea-hog, G. meerschwein, Fr. marsouin, Dan. and Sw. Norwegian, marsvin, Sw. hafssvin. In W. morhwc, sea-hog, is the name of the dolphin and grampus, from the resemblance of these animals to the hog, probably from the roundness of the back, as they appear in the water. It is usually written Porpoise.]

In zoology, cetaceous mammals of the genus Delphinus of Linnæus, but of the genus Phocæna of more recent naturalists, of which about five species are known. There is one species whose back is usually blackish or brown, whence it is called in Dutch, bruinvisch, brown fish; the body is thick toward the head, but more slender toward the tail, which is semilunar. This mammal preys on fish, and seeks food not only by swimming, but by rooting like a hog in the sand and mud, whence some persons suppose the name has been given to it. Of cetaceous fish, we met with porpesses, or as some sailors call them, sea-hogs. – Kalm's Travels. Naturalists do not consider the Cetacea as fishes.