cocoon

Concise Oxford English Dictionary © 2008 Oxford University Press:
cocoon /kəˈkuːn/

▶noun

• 1 a silky case spun by the larvae of many insects for protection as pupae.

  ■ something that envelops someone in a protective or comforting way.

• 2 a covering that prevents the corrosion of metal equipment.

▶verb

• 1 wrap in a cocoon.

• 2 N. Amer. retreat from the stressful conditions of public life into the private world of the family.

– derivatives
cocooner noun.

– origin C17: from Fr. cocon, from med. Provençal coucoun ‘eggshell, cocoon’, dimin. of coca ‘shell’.