The Collaborative International Dictionary of English v.0.48:

Lime \Lime\, n. [AS. l[imac]m; akin to D. lijm, G. leim, OHG.
   l[imac]m, Icel. l[imac]m, Sw. lim, Dan. liim, L. limus mud,
   linere to smear, and E. loam. [root]126. Cf. Loam,
   Liniment.]
   1. Birdlime.
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            Like the lime
            That foolish birds are caught with.   --Wordsworth.
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   2. (Chem.) Oxide of calcium, CaO; the white or gray,
      caustic substance, usually called quicklime, obtained by
      calcining limestone or shells, the heat driving off carbon
      dioxide and leaving lime. It develops great heat when
      treated with water, forming slaked lime, and is an
      essential ingredient of cement, plastering, mortar, etc.
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   Note: Lime is the principal constituent of limestone, marble,
         chalk, bones, shells, etc.
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   Caustic lime, Calcium hydroxide or slaked lime; also, in a
      less technical sense, calcium oxide or quicklime.

   Lime burner, one who burns limestone, shells, etc., to make
      lime.

   Lime pit, a limestone quarry.

   Lime rod, Lime twig, a twig smeared with birdlime; hence,
      that which catches; a snare. --Chaucer.
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The Collaborative International Dictionary of English v.0.48:

Caustic \Caus"tic\, Caustical \Caus"tic*al\, a. [L. caustucs,
   Ge. ?, fr. ? to burn. Cf. Calm, Ink.]
   1. Capable of destroying the texture of anything or eating
      away its substance by chemical action; burning; corrosive;
      searing.
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   2. Severe; satirical; sharp; as, a caustic remark.
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   Caustic curve (Optics), a curve to which the ray of light,
      reflected or refracted by another curve, are tangents, the
      reflecting or refracting curve and the luminous point
      being in one plane.

   Caustic lime. See under Lime.

   Caustic potash, Caustic soda (Chem.), the solid
      hydroxides potash, KOH, and soda, NaOH, or solutions
      of the same.

   Caustic silver, nitrate of silver, lunar caustic.

   Caustic surface (Optics), a surface to which rays reflected
      or refracted by another surface are tangents. Caustic
      curves and surfaces are called catacaustic when formed by
      reflection, and diacaustic when formed by refraction.

   Syn: Stinging; cutting; pungent; searching.
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WordNet (r) 3.0 (2006):

caustic lime
    n 1: a caustic substance produced by heating limestone [syn:
         calcium hydroxide, lime, slaked lime, hydrated
         lime, calcium hydrate, caustic lime, lime hydrate]