Source : Webster's Revised Unabridged Dictionary (1913)

Deliquesce \Del`i*quesce"\, v. i. [imp. & p. p. {Deliquesced};
   p. pr. & vb. n. {Deliquescing}.] [L. deliquescere to melt,
   dissolve; de- + liquescere to become fluid, melt, fr. liquere
   to be fluid. See {Liquid}.] (Chem.)
   To dissolve gradually and become liquid by attracting and
   absorbing moisture from the air, as certain salts, acids, and
   alkalies.

Source : WordNet®

deliquesce
     v 1: melt away in the process of decay; "The fungi eventually
          deliquesced"
     2: melt or become liquid by absorbig moisture from the air;
        "this type of salt deliquesces easily"