A noun appearing as ᴱN. thalf “grease” in Early Noldorin Word-lists of the 1920s, a derivative of primitive ᴱ✶stalqe (PE13/153). It is probably unrelated to similarly formed words like ᴱN. thala “valiant” and ᴱN. thalion “warrior hero” from the same document whose primitive forms begin with stalg- (PE13/153).

Neo-Sindarin: Since this word coexisted with ᴹ√STALAG derivatives in the 1920s, I would assume the same would be true in Tolkien’s later writing. Therefore I’d retain this word as ᴺS. thalph “grease” for purposes of Neo-Sindarin, revised to fit the phonology of later Sindarin and derived from some otherwise-obscure triconsonantal root.