The Collaborative International Dictionary
Hercynian \Her*cyn"i*an\, a. [L. Hercynia silva, Hercynius saltus, the Hercynian forest; cf. Gr. ? ?.] Of or pertaining to an extensive forest in Germany, of which there are still portions in Swabia and the Hartz mountains.
Douglas Harper's Etymology Dictionary
1580s, designating the forest-covered mountains of ancient Germany, from Latin Hercynia (silva) "Hercynian (forest)," related to Greek Orkynios drymos, probably from Old Celtic *Perkunya, from PIE *perq(o)- "oak, oak forest, wooded mountain" (see fir).
Usage examples of "hercynian".
Suebi had retreated to the eaves of the Bacenis Forest, a limitless expanse of beech, oak and birch which eventually fused with an even mightier forest, the Hercynian, and spread untrammeled a thousand miles to far Dacia and the sources of the fabulous rivers flowing down to the Euxine Sea.
When the auspices were taken, the Hercynian forest was assigned to Segovesus.