designating or of the second geologic period of the Paleozoic Era, characterized by the development of abundant marine invertebrates and the first vertebrates
Origin of Ordovician; from Classical Latin Ordovices, ancient Celtic tribe in Wales
the Ordovician Period or its rocks
Of, relating to, or being the period of geologic time from about 488 to 443 million years ago, the second period of the Paleozoic Era. It is characterized by the appearance of primitive fishes and by the supercontinent Gondwana. Some evidence suggests that the first land plants also appeared at this time. See Table at geologic time.
The Ordovician Period.
Origin of OrdovicianFrom Latin Ordovic&emacron;s, an ancient Celtic tribe of Wales, from Celtic Ordovices; see weik-3 in Indo-European roots.