n. pl. sheaths (shēthz, shēths)
a. A usually close-fitting case or covering for a blade, as of a sword.
b. Any of various similar coverings.
2. Biology An enveloping tubular structure, such as the base of a grass leaf that surrounds the stem or the tissue that encloses a muscle or nerve fiber.
3. A close-fitting dress.
4. A condom.
[Middle English schethe, from Old English scēath; see skei- in the Appendix of Indo-European roots.]
(click for a larger image)sheath
Persian sheath (left) and dagger (right)
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