A noun appearing as N. rhaw “lion” in The Etymologies of the 1930s derived from primitive ᴹ✶rāu [rāw] under the root ᴹ√RAW (Ety/RAW), where the initial r was unvoiced to rh as was generally the case in Noldorin. It had a Noldorin plural form of rhui.
Conceptual Development: G. rau “lion” appeared in the Gnomish Lexicon of the 1910s (GL/65), probably a derivative of the early root ᴱ√RAVA like its cognate ᴱQ. rau “lion” (QL/79).
Neo-Sindarin: Since the unvoicing of initial liquids did not occur in Sindarin, many people adapt this word as ᴺS. raw “lion” for purposes of Neo-Sindarin, as suggested in HSD (HSD). Its Sindarin-style plural is more likely to be roe(w) rather than ✱✱rui: compare Sindarin plural S. noeg of naug “dwarf” (UT/100) vs. its Noldorin plural N. nuig (EtyAC/NAUK).
Meaning rectified according to VT/46:10