ordovician

2 definitions found

ordovician - Collaborative International Dictionary of English v.0.48 :

  Ordovician \Or`do*vi"cian\, a. [From L. Ordovices, a Celtic
     people in Wales.] (Geol.)
     Of or pertaining to a division of the Silurian formation,
     corresponding in general to the Lower Silurian of most
     authors, exclusive of the Cambrian. -- n. The Ordovician
     formation.
     [1913 Webster]

ordovician - WordNet (r) 2.1 (2005) :

  Ordovician
      n 1: from 500 million to 425 million years ago; conodonts and
           ostracods and algae and seaweeds [syn: Ordovician,
           Ordovician period]