A Doriathrin noun meaning “the exterior, the outside”, literally “outside the fence” (Ety/GAT(H)). It is a combination of ar- “outside” and gad “fence”. The entry in The Etymologies also had a rejected variant argadon (EtyAC/GAT(H)).
Doriathrin
region
place name. *Hollin
reg
noun. holly
argad
noun. exterior, outside, (lit.) outside the fence
rîm
noun. edge, hem, border
A Doriathrin noun meaning “edge, hem, border” derived from the root ᴹ√RĪ (Ety/RĪ). Its Quenya cognate ᴹQ. ríma suggests a primitive form ✱✶rīmā, where the primitive final vowel vanished in Ilkorin.
tell
noun. close, end, last part
A noun meaning “close, end, last part” derived from the root ᴹ√TELES (EtyAC/TELES). Its Quenya cognates ᴹQ. telle and ᴹQ. tella (< ᴹ✶télesā) suggest a primitive form of ✱✶telesē. The middle [e] would have vanished due to the Ilkorin syncope, after which apparently the [[ilk|[ls] became [ll]]], though this is the only example of this change.
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).