<p><strong>Noun</strong></p><ul><li>A black or brown-speckled seabird of the genus Cepphus, of northern seas, having a sharply pointed black bill, red legs, and white wing patches, as C. grylle (black guillemot) of the North Atlantic Ocean and the similar C. columba (pigeon guillemot) of the North Pacific Ocean.</li><li>(British) A murre of the genus Uria.</li></ul>