Eryn Lasgalen

From Tolkien Gateway

The Wood of Greenleaves (S: Eryn Lasgalen) was the new name chosen by Celeborn and Thranduil for the forest that had been known as Mirkwood for much of the Third Age.[1]

Its name is almost the same as the pre-Mirkwood name Eryn Galen ("Greenwood the Great"),[2] but with the addition of the Sindarin word las ("leaf").