ichthyornisEnglishOxford Dictionary of Englishichthyornis /ˌɪkθiˈɔːnɪs / ▸ noun a fossil gull-like fish-eating bird of the Upper Cretaceous period, with large toothed jaws. Genus Ichthyornis, order Ichthyornithiformes. – ORIGIN modern Latin, from ichthyo- + Greek ornis ‘bird’.