Sindarin name for Mount Q. Oiolossë (PE17/26), usually appearing in the fuller name Amon Uilos. It is a combination of ui “ever” and loss “snow”.
Conceptual Development: In The Etymologies from the 1930s, this name first appeared as (rejected) N. Guilos from the root ᴹ√GEY (Ety/GEY), revised to Uiloss from the root ᴹ√EY (Ety/EY) and finally N. Uilos from the root ᴹ√OY (Ety/OY), with essentially the same derivation as its later Sindarin name.
A flower in Middle-earth about which Tolkien said “like stars bloomed the white flowers of uilos, the Evermind” (UT/49). Elsewhere Evermind was the translation of the Rohirric flower name simbelmynë (LotR/507), so uilos may be its Elvish name but with a different meaning. This word also appears in Amon Uilos, the Sindarin name of Oiolossë “Ever (Snow) White” (S/37). Thus uilos seems to be a combination of ui “ever” and either loss “snow” or gloss “white”.