<p><strong>Noun</strong></p><ul><li>Any of numerous aquatic birds of the subfamily Sterninae of the family Laridae, related to the gulls but usually having a more slender body and bill, smaller feet, a long, deeply forked tail, and a more graceful flight, especially those of the genus Sterna, as S. hirundo (common tern) of Eurasia and America, having white, black, and gray plumage.</li></ul>