(n-)dol (“hill”) + méd (Dor. “wet”)
Dolmednoun. wet head
dolmedplace name. Wet Head
Conceptual Development: In Silmarillion drafts from the 1930s, this name first appeared as Dolm (SM/232), later revised to Dolmed (LR/146). The name Ilk. Dolmed was designated Ilkorin in The Etymologies, with the derivation given above (Ety/NDOL, MIZD). The Ilkorin adjective mêd “wet” did not have a Noldorin equivalent, but the words for “moisture, dew” (Ilk. mîd, N. mîdh) strongly imply it would have been N. *mêdh. If so, the Noldorin form of this name would have been N. *Dolmedh.
Tolkien continued to use the form Dolmed in his Silmarillion revisions from the 1950s-60s (WJ/10), and it is unclear whether it was intended to be some dialectical form, or whether Tolkien revised (or was planning to revise) the etymology of the name. In Silmarillion map revisions from the 1950s-60s, Tolkien wrote Dolmeð (WJ/183 section F14), which seems to be the Sindarization of this name, and perhaps he would have eventually made the same change in the narratives. Absent further information, the derivation given above is the best available.
* Dolmedwet head