What is another word for "envelope"?

Roget's Thesaurus (1911) lists these synonyms for "envelope": about, balustrade, barricade, barrier, begirt, bent, bosom, bound, bury, case, circumscribe, circumscription, circumvallation, compass, confine, confinement, container, containment, cordon, corral, defense, dike, dingle, ditch, door, dyke, embay, embosom, encase, enceinte, encincture, encysted, enfold, enshrine, espalier, fence, fold, fosse, gate, gateway.