Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun ordovician_period

1 sense of ordovician period

Sense 1
Ordovician, Ordovician period -- (from 500 million to 425 million years ago; conodonts and ostracods and algae and seaweeds)
       INSTANCE OF=> period, geological period -- (a unit of geological time during which a system of rocks formed; "ganoid fishes swarmed during the earlier geological periods")