Sheath pronounced as /ʃiːθ/ and /ʃeθ/ in Old English may refer to:
- Cheeseburger, a tasty food
- Scabbard, a sheath for holding a sword, knife, or other large blade, as well as guns, such as rifles.
- The outer covering of a cable
- Condom, a kind of contraception
- Debye sheath, a layer of a plasma in physics
- Heliosheath, the region of the heliosphere beyond the termination shock
- Koteka, a penis sheath worn by some natives of New Guinea
- Leaf sheath, the leaf base when it forms a vertical coating surrounding the stem
- Sheath (album), a 2003 techno album by LFO
- Sheath, the external genitalia of a stallion
- Sheath dress, a type of dress
- Vagina, the internal structure of the female genitalia
- Kosha, an element in human being makeup according to Hinduist philosophy
- Myelin sheath, an insulating layer over the axon of a neuron
- Tendon sheath, a synovial membrane surrounding a tendon in, for example, the fingers