1.
[syn: Ordovician, Ordovician period]
The 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]
WordNet (r) 3.0 (2006):
Ordovician
n 1: from 500 million to 425 million years ago; conodonts and
ostracods and algae and seaweeds [syn: Ordovician,
Ordovician period]