Source : Webster's Revised Unabridged Dictionary (1913)

Lead \Lead\ (l[e^]d), n. [OE. led, leed, lead, AS. le['a]d; akin
   to D. lood, MHG. l[=o]t, G. loth plummet, sounding lead,
   small weight, Sw. & Dan. lod. [root]123]
   1. (Chem.) One of the elements, a heavy, pliable, inelastic
      metal, having a bright, bluish color, but easily
      tarnished. It is both malleable and ductile, though with
      little tenacity, and is used for tubes, sheets, bullets,
      etc. Its specific gravity is 11.37. It is easily fusible,
      forms alloys with other metals, and is an ingredient of
      solder and type metal. Atomic weight, 206.4. Symbol Pb (L.
      Plumbum). It is chiefly obtained from the mineral galena,
      lead sulphide.

   2. An article made of lead or an alloy of lead; as:
      (a) A plummet or mass of lead, used in sounding at sea.
      (b) (Print.) A thin strip of type metal, used to separate
          lines of type in printing.
      (c) Sheets or plates of lead used as a covering for roofs;
          hence, pl., a roof covered with lead sheets or terne
          plates.

                I would have the tower two stories, and goodly
                leads upon the top.               --Bacon

   3. A small cylinder of black lead or plumbago, used in
      pencils.

   {Black lead}, graphite or plumbago; -- so called from its
      leadlike appearance and streak. [Colloq.]

   {Coasting lead}, a sounding lead intermediate in weight
      between a hand lead and deep-sea lead.

   {Deep-sea lead}, the heaviest of sounding leads, used in
      water exceeding a hundred fathoms in depth. --Ham. Nav.
      Encyc.

   {Hand lead}, a small lead use for sounding in shallow water.
      

   {Krems lead}, {Kremnitz lead} [so called from Krems or
      Kremnitz, in Austria], a pure variety of white lead,
      formed into tablets, and called also {Krems, or Kremnitz,
      white}, and {Vienna white}.

   {Lead arming}, tallow put in the hollow of a sounding lead.
      See {To arm the lead} (below).

   {Lead colic}. See under {Colic}.

   {Lead color}, a deep bluish gray color, like tarnished lead.
      

   {Lead glance}. (Min.) Same as {Galena}.

   {Lead line}
      (a) (Med.) A dark line along the gums produced by a
          deposit of metallic lead, due to lead poisoning.
      (b) (Naut.) A sounding line.

   {Lead mill}, a leaden polishing wheel, used by lapidaries.

   {Lead ocher} (Min.), a massive sulphur-yellow oxide of lead.
      Same as {Massicot}.

   {Lead pencil}, a pencil of which the marking material is
      graphite (black lead).

   {Lead plant} (Bot.), a low leguminous plant, genus {Amorpha}
      ({A. canescens}), found in the Northwestern United States,
      where its presence is supposed to indicate lead ore.
      --Gray.

   {Lead tree}.
      (a) (Bot.) A West Indian name for the tropical, leguminous
          tree, {Leuc[ae]na glauca}; -- probably so called from
          the glaucous color of the foliage.
      (b) (Chem.) Lead crystallized in arborescent forms from a
          solution of some lead salt, as by suspending a strip
          of zinc in lead acetate.

   {Mock lead}, a miner's term for blende.

   {Red lead}, a scarlet, crystalline, granular powder,
      consisting of minium when pure, but commonly containing
      several of the oxides of lead. It is used as a paint or
      cement and also as an ingredient of flint glass.

   {Red lead ore} (Min.), crocoite.

   {Sugar of lead}, acetate of lead.

   {To arm the lead}, to fill the hollow in the bottom of a
      sounding lead with tallow in order to discover the nature
      of the bottom by the substances adhering. --Ham. Nav.
      Encyc.

   {To} {cast, or heave}, {the lead}, to cast the sounding lead
      for ascertaining the depth of water.

   {White lead}, hydrated carbonate of lead, obtained as a
      white, amorphous powder, and much used as an ingredient of
      white paint.



   {Red horse}. (Zo["o]l.)
   (a) Any large American red fresh-water sucker, especially
       {Moxostoma macrolepidotum} and allied species.
   (b) See the Note under {Drumfish}.

   {Red lead}.
   (Chem) See under {Lead}, and {Minium}.

   {Red-lead ore}. (Min.) Same as {Crocoite}.

   {Red liquor} (Dyeing), a solution consisting essentially of
      aluminium acetate, used as a mordant in the fixation of
      dyestuffs on vegetable fiber; -- so called because used
      originally for red dyestuffs. Called also {red mordant}.
      

   {Red maggot} (Zo["o]l.), the larva of the wheat midge.

   {Red manganese}. (Min.) Same as {Rhodochrosite}.

   {Red man}, one of the American Indians; -- so called from his
      color.

   {Red maple} (Bot.), a species of maple ({Acer rubrum}). See
      {Maple}.

   {Red mite}. (Zo["o]l.) See {Red spider}, below.

   {Red mulberry} (Bot.), an American mulberry of a dark purple
      color ({Morus rubra}).

   {Red mullet} (Zo["o]l.), the surmullet. See {Mullet}.

   {Red ocher} (Min.), a soft earthy variety of hematite, of a
      reddish color.

   {Red perch} (Zo["o]l.), the rosefish.

   {Red phosphorus}. (Chem.) See under {Phosphorus}.

   {Red pine} (Bot.), an American species of pine ({Pinus
      resinosa}); -- so named from its reddish bark.

   {Red precipitate}. See under {Precipitate}.

   {Red Republican} (European Politics), originally, one who
      maintained extreme republican doctrines in France, --
      because a red liberty cap was the badge of the party; an
      extreme radical in social reform. [Cant]

   {Red ribbon}, the ribbon of the Order of the Bath in England.
      

   {Red sanders}. (Bot.) See {Sanders}.

   {Red sandstone}. (Geol.) See under {Sandstone}.

   {Red scale} (Zo["o]l.), a scale insect ({Aspidiotus
      aurantii}) very injurious to the orange tree in California
      and Australia.

   {Red silver} (Min.), an ore of silver, of a ruby-red or
      reddish black color. It includes {proustite}, or light red
      silver, and {pyrargyrite}, or dark red silver.

   {Red snapper} (Zo["o]l.), a large fish ({Lutlanus aya or
      Blackfordii}) abundant in the Gulf of Mexico and about the
      Florida reefs.

   {Red snow}, snow colored by a mocroscopic unicellular alga
      ({Protococcus nivalis}) which produces large patches of
      scarlet on the snows of arctic or mountainous regions.

   {Red softening} (Med.) a form of cerebral softening in which
      the affected parts are red, -- a condition due either to
      infarction or inflammation.

   {Red spider} (Zo["o]l.), a very small web-spinning mite
      ({Tetranychus telarius}) which infests, and often
      destroys, plants of various kinds, especially those
      cultivated in houses and conservatories. It feeds mostly
      on the under side of the leaves, and causes them to turn
      yellow and die. The adult insects are usually pale red.
      Called also {red mite}.

   {Red squirrel} (Zo["o]l.), the chickaree.

   {Red tape}, the tape used in public offices for tying up
      documents, etc.; hence, official formality and delay.

Source : WordNet®

red lead
     n : a reddish oxide of lead (Pb3O4) used as a pigment in paints
         and in glass and ceramics [syn: {minium}]