The story
- Old Norse · calque ofMyrkviðr“murky wood; dark wood; black forest”
- English todayMirkwood
From Old Norse Myrkviðr (“murky wood; dark wood; black forest”), as anglicised by William Morris and later adopted by J. R. R. Tolkien. Direct derivatives of the name occur as place names in Sweden and Norway.
Etymology from Wiktionary, CC BY-SA 4.0.