Sindarin 

-reth

suffix. -reth

suff. >> Orodreth

Sindarin [(PE17 Sindarin Corpus) PE17:182] < RETE climb. Group: Parma Eldalamberon 17 Sindarin Corpus. Published by

reth

noun. *climber

A word/suffix in 1957 Notes on Names (NN), based on the root √RET and an element in the name S. Orodreth “Mountaineer” (PE17/182). It is thus likely means something like “✱climber”.

Sindarin [PE17/182] Group: Eldamo. Published by

Quenya 

retto

noun. *climber

An apparently Quenya word in 1957 Notes on Names (NN), based on the root √RET and equivalent to S. reth, the latter an element in the name S. Orodreth “Mountaineer” (PE17/182). It is thus likely that Q. retto and S. reth means something like “✱climber”, though it is possible that retto is actually a primitive form.