Sheath (?), n. [OE. schethe, AS. sc&aemac;&edh;, scexa0;&edh;, sc&emac;&edh;; akin to OS. sk&emac;&edh;ia, D. scheede, G. scheide, OHG. sceida, Sw. skida, Dan. skede, Icel. skei&edh;ir, pl., and to E. shed, v.t., originally meaning, to separate, to part. See Shed.]
A case for the reception of a sword, hunting knife, or other long and slender instrument; a scabbard.
The dead knight's sword out of his sheath he drew.
Any sheathlike covering, organ, or part. Specifically:
The base of a leaf when sheathing or investing a stem or branch, as in grasses.
One of the elytra of an insect.
Medullary sheath. Anat. See under Medullary. -- Primitive sheath. Anat. See Neurilemma. -- Sheath knife, a knife with a fixed blade, carried in a sheath. -- Sheath of Schwann. Anat. See Schwann's sheath.
© Webster 1913.