sheath

American  

[sheeth] / ʃiθ /

noun

plural

sheaths

1. a case or covering for the blade of a sword, dagger, or the like.

2. any similar close-fitting covering or case.

3. a condom.

4. Biology. a closely enveloping part or structure, as in an animal or plant.

5. Botany. the leaf base when it forms a vertical coating surrounding the stem.

6. a close-fitting dress, skirt, or coat, especially an unbelted dress with a straight drape.

7. Electricity. the metal covering of a cable.

8. Electronics.

   1. the metal wall of a wave guide.

   2. a space charge formed by ions near an electrode in a tube containing low-pressure gas.

   3. the region of a space charge in a cathode-ray tube.

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verb (used with object)

1. to sheathe.

sheath British  

/ ʃiːθ /

noun

1. a case or covering for the blade of a knife, sword, etc

2. any similar close-fitting case

3. biology an enclosing or protective structure, such as a leaf base encasing the stem of a plant

4. the protective covering on an electric cable

5. a figure-hugging dress with a narrow tapering skirt

6. another name for condom

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verb

1. (tr) another word for sheathe

sheath Scientific  

/ shēth /

1. 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.

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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

Demyelination is the process in which the myelin sheath -- a protective, insulating layer surrounding nerve fibers in the brain and spinal cord -- is damaged or destroyed.

From Science Daily

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

Oligodendrocytes, the cells that produce myelin to insulate nerve fibers, expressed fewer genes required for maintaining and regenerating the myelin sheath.

From Science Daily

Her hands stop when they reach the sheath strap across her chest.

From Literature

The research showed that MS first targets the myelin sheath.

From Science Daily

Related Words

• covering