an auk (Alca torda) of the N Atlantic coasts, with sooty black head and neck, white breast and belly, and a black, compressed bill encircled by a white band: its wings are black as seen from above and white as seen from below
See razorbill in American Heritage Dictionary 4
noun
A large auk (Alca torda) of the northern Atlantic, having black-and-white plumage, a long tail, and a flattened bill.