Sterna is a genus of terns in the bird family Laridae. The genus used to encompass most "white" terns indiscriminately, but mtDNA sequence comparisons have recently determined that this arrangement is paraphyletic. It is now restricted to the typical medium-sized white terns occurring near-globally in coastal regions.

The Antarctic tern is a seabird in the family Laridae. It ranges throughout the southern oceans and is found on small islands around Antarctica as well as on the shores of the mainland. Its diet consists primarily of small fish and crustaceans. It is very similar in appearance to the closely related Arctic tern, but it is stockier, and it is in its breeding plumage in the southern summer, when the Arctic tern has shed old feathers to get its non-breeding plumage. The Antarctic tern does not migrate like the Arctic tern does, but it can still be found on a very large range. This tern species is actually more closely related to the South American tern.