Ordovician Ordovices • ordu · · · Info · Definitions · Characters · · Ordovician · · Text Latin · · Script 10 · · Length Definitions · · · (noun) from 500 million to 425 million years ago; conodonts and ostracods and algae and seaweeds. Synonyms: Ordovician period. · · Noun Definition 1 Characters · · O latin capital letter o U+004F a latin small letter a U+0061 c latin small letter c U+0063 d latin small letter d U+0064 i latin small letter i U+0069 n latin small letter n U+006E o latin small letter o U+006F r latin small letter r U+0072 v latin small letter v U+0076