奧陶紀 [奥－纪]

Jyutping ou3 tou4 gei2
Pinyin ào táo jì

Definitions (CC-CEDICT)
  1. Ordovician (geological period 495-440m years ago)
Definitions (Wiktionary)
  1. name
    the Ordovician period (part of the Paleozoic era, spanning from 485.4 to 443.4 million years ago)