Noun sheath has 3 senses
  1. sheath - a protective covering for a knife or sword
    --1 is a kind of
    protective covering, protective cover, protection
    --1 has particulars:
     aglet, aiglet; fingerstall, cot; holster; scabbard
  2. sheath, case - an enveloping structure or covering enclosing an animal or plant organ or part
    --2 is a kind of covering, natural covering, cover
    --2 has particulars:
     theca; lorica; medullary sheath, myelin sheath; neurolemma, neurilemma; husk
  3. cocktail dress, sheath - a dress suitable for formal occasions
    --3 is a kind of dress, frock