The Collaborative International Dictionary of English v.0.48:

Encystment \En*cyst"ment\, n.
   1. (Biol.) A process which, among some of the lower forms of
      life, precedes reproduction by budding, fission, spore
      formation, etc.
      [1913 Webster]

   Note: The animal (a) first contracts its body to a globular
         mass (b) and then secretes a transparent cyst (c),
         after which the mass divides into two or more parts (as
         in d e), each of which attains freedom by the bursting
         of the cyst, and becomes an individual animal.
         [1913 Webster]

   2. (Zo["o]l.) A process by which many internal parasites,
      esp. in their larval states, become inclosed within a cyst
      in the muscles, liver, etc. See Trichina.
      [1913 Webster]