from
The Collaborative International Dictionary of English v.0.48
Sheath \Sheath\, n. [OE. schethe, AS. sc[=ae][eth],
sce['a][eth], sc[=e][eth]; akin to OS. sk[=e][eth]ia, D.
scheede, G. scheide, OHG. sceida, Sw. skida, Dan. skede,
Icel. skei[eth]ir, pl., and to E. shed, v.t., originally
meaning, to separate, to part. See {Shed}.]
1. A case for the reception of a sword, hunting knife, or
other long and slender instrument; a scabbard.
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The dead knight's sword out of his sheath he drew.
--Spenser.
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2. Any sheathlike covering, organ, or part. Specifically:
(a) (Bot.) The base of a leaf when sheathing or investing
a stem or branch, as in grasses.
(b) (Zool.) One of the elytra of an insect.
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{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}.
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