noun
sheath
SHEETH/ʃiːθ/
A closely fitted enclosing cover.
A leather sheath protects the knife when it is stored.

Etymology
The Old English word for a blade-cover may ultimately reflect the image of a split stick with a blade inserted. That proposed origin is uncertain.
In context
… a knife spends the majority of its lifetime in its sheath so it's essential to properly care for a leather sheath …
More examples
- A plastic sheath surrounds each wire inside the cable.
- She wears a black sheath to the evening reception.
- The tools come with snug sheaths that cover their blades.
Forms
sheath · sheaths
sheathe verb — To enclose in a fitted protective cover.