This noun designates a sheath or case, particularly for a sword. Classical usage extended it to any receptive container—a chest, grave, or bow-case. John uses it in the garden arrest scene when Jesus tells Peter to put his sword back in its sheath. The term emphasizes the sword's resting place, where it belongs when not in use. Classical texts used it for weapon containers and even metaphorically for graves as the body's 'case.' The NT usage is straightforward—the protective covering that holds the blade when sheathed.