Ilkorin name for N. Thorondor appearing in The Etymologies from the 1930s, translated “King of Eagles” (Ety/THOR). It is a combination of thorn “eagle” and tôr “king”.
Doriathrin
thorn
noun. eagle
thorntor
masculine name. King of Eagles
torthurnion
masculine name. King of Eagles
reg
noun. holly
A Doriathrin noun for “holly” attested only in the plural forms regin and region (Ety/ERÉK). It also appeared as an element in the word regorn “holly-tree”. It seems that the latter word replaced reg in the singular, and the original survived only in the plurals, as suggested by Helge Fauskanger (AL-Doriathrin/regorn).
dôn
noun. back
A Doriathrin word for “back” explicitly marked as a noun (Ety/NDAN). Its primitive form might have been ✱✶ndān, so that the primitive long [[ilk|[ā] became [ō]]] and the [[ilk|initial nasal [n] was lost before the stop]] (as suggested by Helge Fauskanger, AL-Doriathrin/dôn).
A noun for “eagle” derived from the root ᴹ√THÓRON (Ety/THOR). Its cognates ᴹQ. soron and N. thoron suggest a primitive form ✱✶thoronē, where the middle [o] was lost due to the Ilkorin syncope. Its plural form is not thurin as printed in The Lost Road, but is actually thurnin matching its singular (EtyAC/THOR), as predicted by Helge Fauskanger (AL-Ilkorin/thorn).