sheath
n. countablen. a protective cover for a knife or a sword. It can also mean any close-fitting cover for an object or a part of the body.
n. a protective casing for a blade or tool; by extension, any close-fitting anatomical or mechanical covering. Often used to describe the protective layer around a nerve or a tight-fitting style of dress.
He slides the sharp knife back into its leather sheath.
The biologist examined the protective sheath surrounding the plant's stem under a microscope.
The warrior drew his sword from its ornate silver sheath, the metal glinting under the harsh midday sun as he prepared for the coming confrontation.
From Middle English sheth, shethe (“holder for a sword, knife, etc., scabbard, sheath”) [and other forms], from Old English sċēaþ (“sheath”), from Proto-West Germanic skaiþiju, from Proto-Germanic skaiþiz (“sheath; covering”), from Proto-Indo-European *skey- (“to dissect, split”) (possibly from the notion of a split stick with a sword inserted). The English word is cognate with Danish skede, Dutch schede, Icelandic skeið, German Scheide, Low German scheed, Norwegian skjede.
A variant of sheathe.
Commonly used in medical contexts to describe the 'myelin sheath' around nerves.