Archaeopteryx (/ˌɑːrkiːˈɒptərɪks/; lit. 'old-wing'), sometimes referred to by its German name, Urvogel (lit. 'original bird' or 'first bird'), is a genus of bird-like dinosaurs. The name derives from the ancient Greek ἀρχαῖος (archaīos), meaning "ancient", and πτέρυξ (ptéryx), meaning "feather" or "wing". Between the late 19th century and the early 21st century, Archaeopteryx was generally accepted by palaeontologists and popular reference books as the oldest known bird (member of the group Avialae). Older potential avialans have since been identified, including Anchiornis, Xiaotingia, and Aurornis.