Defn: A European siluroid fish (Silurus glanis) allied to the cat- fishes. It is the largest fresh-water fish of Europe, sometimes becoming six feet or more in length. See Siluroid.

SHEATH Sheath, n. Etym: [OE. schethe, AS. scæedh, sceáedh, sceedh; akin to OS. skeedhia, D. scheede, G. scheide, OHG. sceida, Sw. skida, Dan. skede, Icel. skeiedhir, pl., and to E. shed, v.t., originally meaning, to separate, to part. See Shed.]

1. A case for the reception of a sword, hunting knife, or other long and slender instrument; a scabbard. The dead knight's sword out of his sheath he drew. Spenser.

2. Any sheathlike covering, organ, or part. Specifically: (a) (Bot.) The base of a leaf when sheathing or investing a stem or branch, as in grasses. (b) (Zoöl.) One of the elytra of an insect. Medullary sheath. (Anat.) See under Medullary. — Primitive sheath. (Anat.) See Neurilemma. — Sheath knife, a knife with a fixed blade, carried in a sheath. — Sheath of Schwann. (Anat.) See Schwann's sheath.

SHEATHBILL
Sheath"bill`, n. (Zoöl.)

Defn: Either one of two species of birds composing the genus Chionis, and family Chionidæ, native of the islands of the Antarctic.seas.

Note: They are related to the gulls and the plovers, but more nearly to the latter. The base of the bill is covered with a saddle-shaped horny sheath, and the toes are only slightly webbed. The plumage of both species is white.

SHEATHE
Sheathe, v. t. [imp. & p. p. Sheathed; p. pr. & vb. n. Sheating.]
Etym: [Written also sheath.]

1. To put into a sheath, case, or scabbard; to inclose or cover with, or as with, a sheath or case. The leopard . . . keeps the claws of his fore feet turned up from the ground, and sheathed in the skin of his toes. Grew. 'T is in my breast she sheathes her dagger now. Dryden.

2. To fit or furnish, as with a sheath. Shak.