Definition of sheaths:
(n) :
A holster for a sword; a scabbard.
(n) :
(by extension) Anything that has a similar shape to a scabbard that is used to hold an object that is longer than it is wide.
(n) :
(electrical engineering) The insulating outer cover of an electrical cable.
(n) :
(fashion) A tight-fitting dress.
(n) :
(botany) The base of a leaf when sheathing or investing a branch or stem, as in grasses.
(n) :
(zoology) The foreskin of certain animals (for example, dogs and horses).