 The genus Pelecanus was first formally described by Linnaeus in 1758 in the tenth edition of his Systema Naturae . He described the distinguishing characteristics as a straight bill hooked at the tip , linear nostrils , a bare face , and fully webbed feet . This early definition included frigatebirds , cormorants , and sulids as well as pelicans . The name comes from the Ancient Greek word pelekan ( πελεκάν ) , which is itself derived from the word pelekys ( πέλεκυς ) meaning " axe " . In classical times , the word was applied to both the pelican and the woodpecker . 
