[sheath] n, pl sheaths [ME shethe, fr. OE sceath; akin to OHG sceida sheath and perh. to L scindere to split--more at shed] (bef. 12c) 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: as a: the tubular fold of skin into which the penis of many mammals is retracted b (1): the lower part of a leaf (as of a grass) when surrounding the stem (2): an ensheathing spathe
3: any of various covering or supporting structures that are applied like or resemble in appearance or function the sheath of a blade: as a: sheathing
2. b: a woman's close-fitting dress usu. worn without a belt c Brit: condom