Akademik

Silurian
adj. & n. Geol.
—adj. of or relating to the third period of the Palaeozoic era with evidence of the first fish and land plants, and the formation of mountains and new land areas.
Usage:
Cf. Appendix II.
—n. this period or system.
Etymology: L Silures, a people of ancient SE Wales

Useful english dictionary. 2012.