Can"cer (?), n. [L. cancer,
cancri, crab, ulcer, a sign of the zodiac; akin to Gr.
karki`nos, Skr. karkaṭa crab, and prob.
Skr. karkara hard, the crab being named from its hard
shell. Cf. Canner, Chancre.] 1.
(Zoöl.) A genus of decapod Crustacea, including
some of the most common shore crabs of Europe and North America,
as the rock crab, Jonah crab, etc. See Crab.
2. (Astron.) (a)
The fourth of the twelve signs of the zodiac. The first
point is the northern limit of the sun's course in summer; hence,
the sign of the summer solstice. See Tropic.
(b) A northern constellation between Gemini
and Leo.
3. (Med.) Formerly, any malignant
growth, esp. one attended with great pain and ulceration, with
cachexia and progressive emaciation. It was so called, perhaps,
from the great veins which surround it, compared by the ancients
to the claws of a crab. The term is now restricted to such a
growth made up of aggregations of epithelial cells, either
without support or embedded in the meshes of a trabecular
framework.
☞ Four kinds of cancers are recognized: (1) Epithelial
cancer, or Epithelioma, in which there is no
trabecular framework. See Epithelioma. (2) Scirrhous
cancer, or Hard cancer, in which the framework
predominates, and the tumor is of hard consistence and slow
growth. (3) Encephaloid, Medullary, or Soft cancer, in
which the cellular element predominates, and the tumor is soft,
grows rapidy, and often ulcerates. (4) Colloid cancer, in
which the cancerous structure becomes gelatinous. The last three
varieties are also called carcinoma.
Cancer cells, cells once believed to be
peculiar to cancers, but now know to be epithelial cells
differing in no respect from those found elsewhere in the body,
and distinguished only by peculiarity of location and
grouping. -- Cancer root (Bot.),
the name of several low plants, mostly parasitic on roots, as
the beech drops, the squawroot, etc. -- Tropic of
Cancer. See Tropic.