The Collaborative International Dictionary of English v.0.48:

Icing \I"cing\, n.
   A coating or covering resembling ice, as of sugar and milk or
   white of egg; frosting.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

ice \ice\ ([imac]s), v. t. [imp. & p. p. iced ([imac]st); p.
   pr. & vb. n. icing ([imac]"s[i^]ng).]
   1. To cover with ice; to convert into ice, or into something
      resembling ice.
      [1913 Webster]

   2. To cover with icing, or frosting made of sugar and milk or
      white of egg; to frost, as cakes, tarts, etc.; as, iced
      cupcakes with a pink icing look delicious.
      [1913 Webster + PJC]

   3. To chill or cool, as with ice; to freeze.
      [1913 Webster]

   4. To kill. [slang]
      [PJC]

WordNet (r) 3.0 (2006):

icing
    n 1: the formation of frost or ice on a surface [syn: frost,
         icing]
    2: a flavored sugar topping used to coat and decorate cakes
       [syn: frosting, icing, ice]
    3: (ice hockey) the act of shooting the puck from within your
       own defensive area the length of the rink beyond the
       opponent's goal [syn: icing, icing the puck]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "icing":
   Jell-O, blancmange, bonus, candy, coating, comfit, compote,
   confection, confectionery, confiture, conserve, dividend, extra,
   extra added attraction, fringe benefit, frosting, gelatin, glaze,
   honey, jam, jelly, marmalade, meringue, mousse, preserve, reward,
   sweet, sweet stuff, sweetmeat, sweets, topping, tutti-frutti,
   whipped cream