sheath
Americannoun
plural
sheaths-
a case or covering for the blade of a sword, dagger, or the like.
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any similar close-fitting covering or case.
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a condom.
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Biology. a closely enveloping part or structure, as in an animal or plant.
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Botany. the leaf base when it forms a vertical coating surrounding the stem.
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a close-fitting dress, skirt, or coat, especially an unbelted dress with a straight drape.
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Electricity. the metal covering of a cable.
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Electronics.
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the metal wall of a wave guide.
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a space charge formed by ions near an electrode in a tube containing low-pressure gas.
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the region of a space charge in a cathode-ray tube.
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verb (used with object)
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to sheathe.
noun
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a case or covering for the blade of a knife, sword, etc
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any similar close-fitting case
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biology an enclosing or protective structure, such as a leaf base encasing the stem of a plant
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the protective covering on an electric cable
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a figure-hugging dress with a narrow tapering skirt
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another name for condom
verb
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(tr) another word for sheathe
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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.
Other Word Forms
- sheathless adjective
- sheathlike adjective
- sheathy adjective
Etymology
Origin of sheath
before 950; Middle English s ( c ) heth ( e ), Old English scēath; cognate with German Scheide; shed 2
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The road ahead, once hidden in a sheath of forest, is now a scar carved into the side of a landscape of exposed soil and the standing carcasses of tens of thousands of blackened trees.
From Los Angeles Times • Dec. 28, 2025
Oligodendrocytes, the cells that produce myelin to insulate nerve fibers, expressed fewer genes required for maintaining and regenerating the myelin sheath.
From Science Daily • Nov. 24, 2025
In MS, the immune system mistakenly attacks the myelin sheath, a protective layer that insulates nerve fibers.
From Science Daily • Oct. 11, 2025
Mr Rowe was carrying a Japanese-made trowel in its sheath, a small Japanese gardener's sickle and a peeling knife, along with a trug of vegetables.
From BBC • Aug. 6, 2025
His voice was quiet, but all the other boys suddenly fell still, for in his tone as in Jasper’s the spite between them now sounded plain and clear as steel coming out of a sheath.
From "A Wizard of Earthsea" by Ursula K. Le Guin
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.