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).
boronnoun/adjective. steadfast, steadfast, trusty man, faithful vassal, trusty man, faithful vassal
A word meaning “steadfast, trusty man, faithful vassal” developed from the primitive form ᴹ✶bóron- (Ety/BOR). Because the initial syllable was stressed in the primitive form, the initial [bor-] did not reduce to [br-] as it did when the primitive vowel was unstressed. The glosses seem to indicate that it could be used as an adjective “steadfast” or a noun “trusty man, faithful vassal”. However, it is possible that the first part of the gloss is meant to read “steadfast/trusty man”, so that the word is only an noun.
* regnoun. 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).