—n. 1. a case or covering for the blade of a sword, dagger, or the like.
2. any similar close-fitting covering or case.
3. a condom.
4. Biol.a closely enveloping part or structure, as in an animal or plant.
5. Bot.the leaf base when it forms a vertical coating surrounding the stem.
6. a close-fitting dress, skirt, or coat, esp. an unbelted dress with a straight drape.
7. Elect.the metal covering of a cable.
8. Electronics. a. the metal wall of a wave guide.
b. a space charge formed by ions near an electrode in a tube containing low-pressure gas.
c. the region of a space charge in a cathode-ray tube.