Dimholt
From Tolkien Gateway
Dimholt, was a fir-wood of dark trees at the entrance to the Dark Door within Dunharrow.
The Dimholt was traversed by a double row of standing stones that marked an ancient roadway leading away into the east, towards the Dwimorberg and the Paths of the Dead. Deep within a wood of black trees stood a single great stone to mark the way, and beyond that, among the roots of the Dwimorberg, lay the Dark Door of The Dead.[1]
Etymology
The word is supposed to be Rohirric and the element dim has the archaic sense "obscure, secret". Holt means "wood" in occasional poetic use.[2]