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

• armor
• capsule
• case
• casing
• cocoon
• cover
• covering
• encasement
• housing
• hull
• husk
• jacket
• pod
• shell

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

Microplastics tend to gather in fat cells in the insulating sheath that wraps around the brain's neurons and helps to regulate signal transmission—this accumulation may explain why microplastic concentrations in the brain are higher than in other organs, the team said. —Anders Fogh Rasmussen, Newsweek, 5 Feb. 2025

Try a sparkly mini by Ganni or an asymmetrical sheath from Taller Marmo. —Christina Holevas, Vogue, 21 Dec. 2024

Police found a Ka-Bar knife sheath under Mogen's body that prosecutors say contained Kohberger's DNA. —Stepheny Price, Fox News, 23 Jan. 2025

Investigators found the leather sheath for a combat-style knife on the bed of one of the victims, next to her body, according to police. —Kevin Fixler, Idaho Statesman, 11 Jan. 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

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