The Sindarin word for “east”, cognate of Q. rómen (LotR/1116, 1123). It was ultimately derived from the root √RŌ/ORO “rise” (Ety/RŌ), and so likely originally meant “rising” as in “rising sun” (PE22/35).
Conceptual Development: The word N. rhûn “east” appeared in The Etymologies from the 1930s along with ᴹQ. rómen, both derived from ᴹ√RŌ (Ety/RŌ). At the time, there were no problems with this equivalence, since [[n|initial [r] was unvoiced]] in Noldorin. Tolkien went on to use both these forms in The Lord of the Rings.
Unfortunately, Tolkien later abandoned the unvoicing of initial r in Sindarin, making these two forms problematic. Tolkien considered modifying the Sindarin form to rûn (PE17/88) or the Quenya form to hrómen (PE17/18). The latter was probably derived from an s-strengthened form of the root ᴹ√SRŌ (PE22/127), where the initial sr- would become voiceless [r] in both Quenya and Sindarin. Ultimately, though, he left both forms alone. Perhaps he decided the s-strengthening of the root was a Sindarin-only variant.
n. #east. Q. rómen.