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 two-time Olympic champion from Norway hadn’t raced since having surgery early this year to clean up scar tissue on the protective sheath around his left Achilles tendon. — ABC News, 10 Aug. 2026

Gay then allegedly returned to his vehicle and came back with a machete in its sheath. — Natasha Holt, FOXNews.com, 9 Aug. 2026

Whether that means a grass-grazing train, a full and feminine skirt, or an easy breezy sheath, there’s a backyard wedding dress sure to suit your style. — Rosie Jarman, Vogue, 6 Aug. 2026

Alcaraz is managing tenosynovitis, an injury in which fluid accumulates in the sheath that protects a key tendon in the wrist. — Matthew Futterman, New York Times, 4 Aug. 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

• 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