The Collaborative International Dictionary of English v.0.48:

molting \molting\ n.
   The act or process by which an animal molts; especially, the
   periodic shedding of the cuticle in arthropods or the outer
   skin in reptiles, or feathers in birds.

   Syn: molt, moult, moulting, ecdysis.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Molt \Molt\, Moult \Moult\, v. i. [imp. & p. p. Molted or
   Moulted; p. pr. & vb. n. Molting or Moulting.] [OE.
   mouten, L. mutare. See Mew to molt, and cf. Mute, v. t.]
   [The prevalent spelling is, perhaps, moult; but as the u
   has not been inserted in the otherwords of this class, as,
   bolt, colt, dolt, etc., it is desirable to complete the
   analogy by the spelling molt.]
   To shed or cast the hair, feathers, skin, horns, or the like,
   as an animal or a bird. --Bacon.
   [1913 Webster] Molt

WordNet (r) 3.0 (2006):

molting
    n 1: periodic shedding of the cuticle in arthropods or the outer
         skin in reptiles [syn: molt, molting, moult,
         moulting, ecdysis]