The region of Númenor ruled by Hallatan (UT/197). Its initial element is most likely the prefixal form hyara- of hyarmen “south”. The second element looks like a derivative of the root √STOR “steadfast” (PE17/186). It may also be related to torna “hard”, whose superlative form anastorna indicates that it might be from the same root (PE17/56). If so, the name mean might something like “✱South Fastness”.
Quenya
Hyarastorni
south
hyarastorni
place name. ?South Fastness
Elements
Word Gloss hyar- “left-hand, south” STOR “steadfast”
hyarmen
south
hyarmen, Hyarmen noun "south" (SA, SA:men, KHYAR), literally "lefthand-direction" (VT49:12), since the Elves named the directions as they were to a person facing the Blessed Realm in the West Also name of tengwa #33 (Appendix E). In Hyarmendacil masc.name, "South-victor" (Appendix A), apparently also in the place-name Hyarmentir (name of a mountain; the element -tir means *"watch[ing point]".) (SA) Hyarnustar "the Southwestlands" of Númenor; Hyarrostar the "Southeastlands" (UT:165)
Harmen
south
[Harmen] noun "south" (MEN)(Changed to hyarmen.)
Hyarastorni place-name, region in Númenor, apparently including hyar- "south" and perhaps orni "trees" (UT:210)