sea swallow

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various terns, especially a common tern (Sterna hirundo) that breeds within the Arctic Circle.

Wiktionary

1. n. a tern.

GNU Webster's 1913

1. The common tern.
2. The storm petrel.
3. The gannet.
4. See Cornish chough, under Chough.

WordNet 3.0

1. n. common tern of Eurasia and America having white black and grey plumage