Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
The second period in the Paleozoic era: 505 to 438 million years ago.
Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited
Switch to new thesaurus
|Noun||1.||Ordovician period - from 500 million to 425 million years ago; conodonts and ostracods and algae and seaweeds|
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.