The silky protective case spun by the larvae of some insects in which they metamorphose, the pupa.
Any similar protective case, whether real or metaphorical.
To envelop in a protective case.
To withdraw into such a case.
To distinguish, make obvious the distinction between (two things) or of (something).
Used other than figuratively or idiomatically: to separate or isolate.
To select (something or someone) for a specific purpose.