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]

WordNet (r) 3.0 (2006):

thawing
    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]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "thawing":
   colliquation, colliquative, decoagulation, deliquescence,
   deliquium, dissolution, dissolutional, dissolutive, dissolving,
   fluidification, fluidization, fusibility, fusing, fusion, leaching,
   liquation, liquefaction, liquefactive, liquefying, liquescence,
   liquescency, lixiviation, melting, percolation, running,
   solubilization, solution, thaw, thermoplasticity, unclotting