This verb appeared in its Noldorin-style infinitive form N. rhenio in The Etymologies of the 1930s, derived from primitive ᴹ✶ramya- under the root ᴹ√RAM having do with wings (Ety/RAM). The verb was glossed “fly, sail; wander”, but the last gloss “wander” was technically for a separate verb N. rhenio, elsewhere translated “to stray” and based on the root ᴹ√RAN “wander, stray” (Ety/RAN). The two verbs collided because ancient my became ny in Noldorin of the 1930s.
Neo-Sindarin: Many Neo-Sindarin writers adapt this verb as ᴺS. renia- “to sail, fly” for purposes of Neo-Sindarin, as suggested by David Salo (GS/282), since the unvoicing of initial r to rh was a feature of Noldorin of the 1930s but not Sindarin of the 1950s and 60s. Didier Willis instead suggested ᴺS. revia- (HSD/revia) assuming that my > ny was also a Noldorin-only change, but there is strong evidence that ancient my became ny in Sindarin of the 1950s and 60s as well, notably √MAY > amya- > anya- > S. ein- “excellent, admirable” (PE17/163), published after Willis made his suggestion.
A verb in The Etymologies of the 1930s glossed “to stray” appearing in its Noldorin-style infinitive form rhenio under the root ᴹ√RAN “wander, stray” (Ety/RAN). In the entry for ᴹ√RAM it was glossed “wander”, along with a homonym N. rhenio⁽⁾ “fly, sail” derived from ᴹ✶ramya-. The two verbs collided because ancient my became ny in Noldorin/Sindarin.
Neo-Sindarin: Many Neo-Sindarin writers adapt this verb as ᴺS. renia- “to stray, wander” for purposes of Neo-Sindarin, as suggested in HSD (HSD), since the unvoicing of initial r to rh was a feature of Noldorin of the 1930s but not Sindarin of the 1950s and 60s.