Earliest Elvish name for the Wetwang appearing in Lord of the Rings drafts from the 1940s (TI/268), a combination of palath “surface” and otherwise unattested nenui “wet”, as suggested by Roman Rausch (EE/2.38).
Noldorin
palath
noun. surface
palath
noun. iris
palath
noun. surface
dalath
noun. flat surface, plane
dalath
noun. flat land, plain, (wide) valley
palath nenui
place name. Wetwang
palath-ledin
place name. Gladden Fields
nindalf
place name. Wetwang
A word for “surface” in The Etymologies of the 1930s under the root ᴹ√PAL “wide (open)” (Ety/PAL).