A holster for a sword; a scabbard.

(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.

(botany) The base of a leaf when sheathing or investing a branch or stem, as in grasses.

(electrical engineering) The insulating outer cover of an electrical cable.

(entomology) One of the elytra of an insect.

(fashion) A tight-fitting dress.

(zoology) The foreskin of certain animals (for example, dogs and horses).

(Britain, informal) A condom.

Alternative spelling of sheathe