noun

1. the silky or fibrous case which the larvae of certain insects spin about themselves for shelter during the pupa stage
2. any protective cover like this, as the egg capsule of certain spiders, leeches, etc.
3. any cover used to waterproof or protect something, esp. military equipment for transport or storage

Etymology: Fr cocon < Prov coucoun, egg shell, dim. of coca, shell-like container < ML coco, shell, hull

transitive verb

1. to enclose protectively, as in a cocoon
2. to isolate (oneself)