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.
Note: 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}.