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 of sheath

• 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

The religious article, called a kirpan, cannot be longer than 10 inches and must be contained in a sheath to wear in City Hall, according to the ordinance. —Ishani Desai, Sacbee.com, 11 Mar. 2026

For cocktail dresses with some fabric texture, consider this tulle midi dress or this lace sheath dress—both of which come in a multitude of spring color options. —Anna Popp, Travel + Leisure, 8 Mar. 2026

Investigators were able to tie him to the killings using DNA retrieved from the button snap of a knife sheath that was left near one of the slain students' bodies. —Anna Schecter, CBS News, 21 Feb. 2026

In the Kohberger case, investigators acknowledged the FBI used DNA from a a knife sheath found at the crime scene in a genetic investigation. —Andy Rose, CNN Money, 19 Feb. 2026

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