Sheath"bill` (?), n. Zool.
Either one of two species of birds composing the genus Chionis, and family Chionidae, native of the islands of the Antarctic.seas.
⇒ 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.
© Webster 1913.