The Collaborative International Dictionary of English v.0.48:

thaw \thaw\ (th[add]), v. i. [imp. & p. p. Thawed (th[add]d);
   p. pr. & vb. n. Thawing.] [AS. [thorn][=a]wian,
   [thorn][=a]wan; akin to D. dovijen, G. tauen, thauen (cf.
   also verdauen to digest, OHG. douwen, firdouwen), Icel.
   [thorn]eyja, Sw. t["o]a, Dan. t["o]e, and perhaps to Gr.
   th`kein to melt. [root]56.]
   1. To melt, dissolve, or become fluid; to soften; -- said of
      that which is frozen; as, the ice thaws.
      [1913 Webster]

   2. To become so warm as to melt ice and snow; -- said in
      reference to the weather, and used impersonally.
      [1913 Webster]

   3. Fig.: To grow gentle or genial. Compare cold[4], a. and
      hard[6], a.
      [1913 Webster +PJC]

The Collaborative International Dictionary of English v.0.48:

thaw \thaw\, v. t.
   To cause (frozen things, as earth, snow, ice) to melt,
   soften, or dissolve.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

thaw \thaw\, n.
   The melting of ice, snow, or other congealed matter; the
   resolution of ice, or the like, into the state of a fluid;
   liquefaction by heat of anything congealed by frost; also, a
   warmth of weather sufficient to melt that which is congealed.
   --Dryden.
   [1913 Webster]

WordNet (r) 3.0 (2006):

thaw
    n 1: the process whereby heat changes something from a solid to
         a liquid; "the power failure caused a refrigerator melt
         that was a disaster"; "the thawing of a frozen turkey takes
         several hours" [syn: thaw, melt, thawing, melting]
    2: warm weather following a freeze; snow and ice melt; "they
       welcomed the spring thaw" [syn: thaw, thawing, warming]
    3: a relaxation or slackening of tensions or reserve; becoming
       less hostile; "the thaw between the United States and Russia
       has led to increased cooperation in world affairs"
    v 1: become or cause to become soft or liquid; "The sun melted
         the ice"; "the ice thawed"; "the ice cream melted"; "The
         heat melted the wax"; "The giant iceberg dissolved over the
         years during the global warming phase"; "dethaw the meat"
         [syn: dissolve, thaw, unfreeze, unthaw, dethaw,
         melt]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "thaw":
   bend, colliquate, cut, decoagulate, decoct, defrost, deliquesce,
   dissolve, fluidify, fluidize, flux, forbear, forgive, fuse,
   fusibility, fusion, give quarter, have mercy upon, have pity,
   heat up, hold in solution, infuse, leach, let up on, liquation,
   liquefy, liquesce, liquidize, lixiviate, melt, melt down, melting,
   pardon, percolate, refine, relax, relent, render, reprieve, run,
   running, smelt, soften, solubilize, solve, spare, take pity on,
   thawing, thermoplasticity, thin, unbend, unclot, unfreeze, warm,
   warm up, yield