Source : Webster's Revised Unabridged Dictionary (1913)

Milk \Milk\, n. [AS. meoluc, meoloc, meolc, milc; akin to
   OFries. meloc, D. melk, G. milch, OHG. miluh, Icel. mj?ok,
   Sw. mj["o]lk, Dan. melk, Goth. miluks, G. melken to milk,
   OHG. melchan, Lith. milszti, L. mulgere, Gr. ?. ????. Cf.
   {Milch}, {Emulsion}, {Milt} soft roe of fishes.]
   1. (Physiol.) A white fluid secreted by the mammary glands of
      female mammals for the nourishment of their young,
      consisting of minute globules of fat suspended in a
      solution of casein, albumin, milk sugar, and inorganic
      salts. ``White as morne milk.'' --Chaucer.

   2. (Bot.) A kind of juice or sap, usually white in color,
      found in certain plants; latex. See {Latex}.

   3. An emulsion made by bruising seeds; as, the milk of
      almonds, produced by pounding almonds with sugar and
      water.

   4. (Zo["o]l.) The ripe, undischarged spat of an oyster.

   {Condensed milk}. See under {Condense}, v. t.

   {Milk crust} (Med.), vesicular eczema occurring on the face
      and scalp of nursing infants. See {Eczema}.

   {Milk fever}.
      (a) (Med.) A fever which accompanies or precedes the first
          lactation. It is usually transitory.
      (b) (Vet. Surg.) A form puerperal peritonitis in cattle;
          also, a variety of meningitis occurring in cows after
          calving.

   {Milk glass}, glass having a milky appearance.

   {Milk knot} (Med.), a hard lump forming in the breast of a
      nursing woman, due to obstruction to the flow of milk and
      congestion of the mammary glands.

   {Milk leg} (Med.), a swollen condition of the leg, usually in
      puerperal women, caused by an inflammation of veins, and
      characterized by a white appearance occasioned by an
      accumulation of serum and sometimes of pus in the cellular
      tissue.

   {Milk meats}, food made from milk, as butter and cheese.
      [Obs.] --Bailey.

   {Milk mirror}. Same as {Escutcheon}, 2.

   {Milk molar} (Anat.), one of the deciduous molar teeth which
      are shed and replaced by the premolars.

   {Milk of lime} (Chem.), a watery emulsion of calcium hydrate,
      produced by macerating quicklime in water.

   {Milk parsley} (Bot.), an umbelliferous plant ({Peucedanum
      palustre}) of Europe and Asia, having a milky juice.

   {Milk pea} (Bot.), a genus ({Galactia}) of leguminous and,
      usually, twining plants.

   {Milk sickness} (Med.), a peculiar malignant disease,
      occurring in some parts of the Western United States, and
      affecting certain kinds of farm stock (esp. cows), and
      persons who make use of the meat or dairy products of
      infected cattle. Its chief symptoms in man are
      uncontrollable vomiting, obstinate constipation, pain, and
      muscular tremors. Its origin in cattle has been variously
      ascribed to the presence of certain plants in their food,
      and to polluted drinking water.

   {Milk snake} (Zo["o]l.), a harmless American snake
      ({Ophibolus triangulus}, or {O. eximius}). It is variously
      marked with white, gray, and red. Called also {milk
      adder}, {chicken snake}, {house snake}, etc.

   {Milk sugar}. (Physiol. Chem.) See {Lactose}, and {Sugar of
      milk} (below).

   {Milk thistle} (Bot.), an esculent European thistle ({Silybum
      marianum}), having the veins of its leaves of a milky
      whiteness.

   {Milk thrush}. (Med.) See {Thrush}.

   {Milk tooth} (Anat.), one of the temporary first set of teeth
      in young mammals; in man there are twenty.

   {Milk tree} (Bot.), a tree yielding a milky juice, as the cow
      tree of South America ({Brosimum Galactodendron}), and the
      {Euphorbia balsamifera} of the Canaries, the milk of both
      of which is wholesome food.

   {Milk vessel} (Bot.), a special cell in the inner bark of a
      plant, or a series of cells, in which the milky juice is
      contained. See {Latex}.

   {Rock milk}. See {Agaric mineral}, under {Agaric}.

   {Sugar of milk}. The sugar characteristic of milk; a hard
      white crystalline slightly sweet substance obtained by
      evaporation of the whey of milk. It is used in pellets and
      powder as a vehicle for homeopathic medicines, and as an
      article of diet. See {Lactose}.

Source : WordNet®

Silybum marianum
     n : tall Old World biennial thistle with large clasping
         white-blotched leaves and purple flower heads;
         naturalized in California and South America [syn: {milk
         thistle}, {lady's thistle}, {Our Lady's mild thistle}, {holy
         thistle}, {blessed thistle}]