Onychoprion, the "brown-backed terns", is a genus of seabirds in the tern family. The genus name is from Ancient Greek onux, "claw", and "prion", nail. Although the genus was first described in 1832 by Johann Georg Wagler the four species in the genus were until 2005 retained in the larger genus Sterna, the genus that holds most terns. \n* Genus Onychoprion – "brown-backed" terns. \n* Spectacled tern, Onychoprion lunatus \n* Bridled tern, Onychoprion anaethetus \n* Sooty tern, Onychoprion fuscatus \n* Aleutian tern, Onychoprion aleuticus