Effloresce \Ef`flo*resce"\, v. i. [imp. & p. p. Effloresced;
   p. pr.
         & vb. n. Efflorescing.] [L.
         efflorescere to bloom,
  
         blossom; ex + florescere to begin to blossom, incho., fr.
 
          florere to blossom, fr. flos a flower. See Flower.]
  
         1. To blossom forth. --Carlyle.
      [1913 Webster]

  
         2. (Chem.) To change on the surface, or throughout, to a
  
            whitish, mealy, or crystalline powder, from a gradual
  
            decomposition, esp. from the loss of water, on simple
  
            exposure to the air; as, Glauber's salts, and many
         others,
      effloresce.
      [1913 Webster]

   3. To
         become covered with a whitish crust or light
     
         crystallization, from a slow chemical change between some
 
             of the ingredients of the matter covered and an acid
  
            proceeding commonly from an external source; as, the
         walls
      of limestone caverns sometimes effloresce with
         nitrate of
      calcium in consequence of the action of
         nitric acid formed
      in the atmosphere.
      [1913
         Webster]