Sterna is a genus of terns in the bird family Sternidae. Sterna is derived from Old English "stearn" which appears in the poem The Seafarer; a similar word was used to refer to terns by the Frisians. It 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.