sheath

noun

ˈshēth 

plural sheaths ˈshēt͟hz  ˈshēths 

1

: a case for a blade (as of a knife)

2

: an investing cover or case of a plant or animal body or body part: such as

a

: the tubular fold of skin into which the penis of many mammals is retracted

b(1)

: the lower part of a leaf when surrounding the stem

(2)

: an ensheathing spathe

3

: any of various covering or supporting structures that resemble in appearance or function the sheath of a blade: such as

a

: sheathing sense 2

b

: a woman's close-fitting dress that is usually worn without a belt

c

British : condom sense 1

Synonyms

• casing
• covering
• housing
• jacket
• shell
• cover
• case

Examples of sheath in a Sentence

the sheath of a sword

a piece of wire covered with a plastic sheath

Recent Examples on the Web

Their evidence would have included DNA evidence that linked him to a knife sheath found at the crime scene. —July 2, CBS News, 2 July 2025

He was arrested in December 2022 in Pennsylvania after forensic evidence linked him to the murders, including DNA found on a knife sheath at the crime scene and cellphone data placing him near the victims' home multiple times. Jan. 4, 2023 Kohberger was extradited to Idaho on Jan. 4, 2023. —Sarah Rumpf-Whitten , Michael Ruiz, FOXNews.com, 2 July 2025

But in court filings, defense lawyers have floated the idea that the knife sheath found in the Moscow home could have been planted by the real killer. —Jean Casarez, CNN Money, 28 June 2025

Intrigued, researchers sent the sheath for further analysis and CT scans. —Aspen Pflughoeft, Miami Herald, 20 June 2025

Word History

Etymology

Middle English shethe, going back to Old English scǣþ, scēaþ (Northumbrian sceǣþ), scēþ, going back to Germanic *skaiþjō or *skaiþō (whence also Old Frisian skēthe "sheath," Old Saxon skēdia, skēthia, Old High German skeida, Old Icelandic skeiðir, plural), probably noun derivative of *skaiđan-/skaiþan- "to separate, divide" — more at shed entry 1

Note: The original meaning of the Germanic noun was presumably "something split, separated," i.e., two pieces that are split (literally or metaphorically) and that together held the blade; note that the Old Norse noun was plural (the singular skeið meant "weaver's reed, silver spoon").

First Known Use

before the 12th century, in the meaning defined at sense 1

Phrases Containing sheath

• medullary sheath
• myelin sheath
• sheath knife

Rhymes for sheath

• neath
• teeth
• wreath
• beneath
• bequeath
• underneath

Kids Definition

sheath

noun

ˈshēth 

plural sheaths ˈshēt͟hz 

ˈshēths

1

: a case for a blade (as of a knife)

2

: a covering especially of a body part that is like a sheath in form or use

Medical Definition

sheath

noun

ˈshēth 

plural sheaths ˈshēt͟hz  ˈshēths 

1

: an investing cover or case of a plant or animal body or body part: as

a

: the tubular fold of skin into which the penis of many mammals is retracted

b

: the connective tissue of an organ or part that binds together its component elements and holds it in place

2

: condom sense 1

sheathed adjective