| English noun: Ordovician period | |||
| 1. | Ordovician period (time) from 500 million to 425 million years ago; conodonts and ostracods and algae and seaweeds | ||
| Synonyms | Ordovician | ||
| Instance hypernym | geological period, period | ||
| Part meronym | Paleozoic, Paleozoic era | ||