Real Dictionary

cocoon
countable noun: A cocoon is a covering of silky threads that the larvae of moths and other insects make for themselves before they grow into adults.
countable noun: If you are in a cocoon of something, you are wrapped up in it or surrounded by it.

cocoon in American English
the silky or fibrous case which the larvae of certain insects spin about themselves for shelter during the pupa stage
to enclose protectively, as in a cocoon
intransitive verb: to produce a cocoon
noun: the silky envelope spun by the larvae of many insects, as silkworms, serving as a covering while they are in the pupal stage
transitive verb: to wrap or enclose tightly, as if in a cocoon

cocoon in British English
noun: a silky protective envelope secreted by silkworms and certain other insect larvae, in which the pupae develop
verb: to wrap in a cocoon