1. (Science: biology) a process which, among some of the lower forms of life, precedes reproduction by budding, fission, spore formation, etc.
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.
2. (Science: zoology) a process by which many internal parasites, especially. In their larval states, become inclosed within a cyst in the muscles, liver, etc. See trichina.