Noun: Ordovician ,or-du'vi-sh(ee-)un or ,or-du'vi-see-un
- The period from 500 million to 425 million years ago; characterized by conodonts and ostracods and algae and seaweeds
- Ordovician period
Type of: geological period, period
Part of: Palaeozoic [Brit, Cdn], Paleozoic, Paleozoic era
Encyclopedia: Ordovician