sheath

(sheth) [A.S. scceth.] i. Any enveloping structure, such as the membranous covering of a muscle, nerve, or blood-ve el. 2. Vagina (i). 3. The prepuce of a horse, dentinal s., dural s., femoral s., see the adjectives. Henle's s., Mauthner's s., Schwann's s., see the proper names.