Emily Dickinson Lexicon

CAN'CER, n. [L. cancer; Sax. cancre; Fr. cancre; D. kanker; Sp. cangrejo, cancro; It. cancro, canchero; Gr. κογχη. This seems to be the same word, though applied to the shell; καρκινος, a cancer, is a different word. From the Greek, the Latins have concha, Eng. conch. But n is not radical; for this is undoubtedly the W. cocos, Eng. cockle, Fr. coquille, coque, It. coccia. These words are probably from the same root as Sp. cocar, to wrinkle, twist, or make wry faces; Ir. cuachaim, to fold; Eng. cockle, to shrink or pucker; verbs which give the primary sense. It is to be noted that cancer and canker are the same word; canker being the original pronunciation.]

1. The crab or crab-fish. This genus of animals have generally eight legs, and two claws which serve as hands; two distant eyes, supported by a kind of peduncles, and they are elongated and movable. They have also two clawed palpi, and the tail is jointed. To this genus belong the lobster, shrimp, cray-fish, &c.
2. In astronomy, one of the twelve signs of the zodiac, represented by the form of a crab, and limiting the sun's course northward in summer; hence, the sign of the summer solstice.
3. In medicine, a roundish, hard, unequal, scirrous tumor of the glands, which usually ulcerates, is very painful, and generally fatal.