An Ilkorin prefix meaning “outside, beside”, the same as in Quenya and Noldorin (Ety/AR²).
ar-prefix. outside, beside
A noun for “king” derived from primitive ᴹ✶tār(ō), also appearing in its plural form tórin (Ety/TĀ, BAL). Tolkien said that it was “only used of the legitimate kings of whole tribes”, though apparently it also survived in compounds like Torthurnion “King of Eagles” (Ety/THOR) and Balthor “Vala-king” (Ety/BAL). It is an example of how [ā] became [ō] in Ilkorin, as noted by Helge Fauskanger (AL-Ilkorin/tôr).