(pl. roen, idh roen), coll. pl. ronath. Cf. the ending -ron at the end of month-names. Raun is basically the adj. ”straying, wandering” used as a noun, hence identifying the Moon as ”the Wanderer”. – The ”Noldorin” form rhân presupposes a different primitive form and may not correspond to S ✱rân as would normally be supposed.
Noldorin
rhân
noun. Moon
ithil
noun. Moon
A word for “moon”, equivalent of Q. Rána, attested in later writings only as the element -rawn in the archaic form S. †cýrawn “new-moon”, in modern speech cýron (VT48/7). Based on its use in this word, as well as in N. cúran “crescent moon” [ᴺS. cúron], it seems this is the ordinary word for “Moon” (or “moon”) as a celestial body, as opposed to S. Ithil which is the proper name of the moon, equivalent to English “Luna”. Raun is derived from primitive ✶rānā from the root √RAN “wander”, and hence originally meant something like “Wanderer”, though its Quenya equivalent is usually translated “Wayward”.
Conceptual Development: A very similar form G. Rân “the moon” appeared in Gnomish Lexicon of the 1910s (GL/64), as well as ᴱN. rán “moon” in Early Noldorin Word-lists of the 1920s (PE13/152), though in this period its etymology is unclear. It appeared as N. Rhân “Moon” in The Etymologies of the 1930s, derived from the root ᴹ√RAN “wander, stray” (Ety/RAN), but in this period its Quenya equivalent was ᴹQ. Rana with short a. In later writings the Quenya form became Q. Rána, requiring a change to S. Raun since ancient ā became au in Sindarin.