Archaic form of the name Rohan (LotR/1115), a combination of roch “horse” and the archaic suffix †-ian(d) “land” (Let/382).
Conceptual Development: In Lord of the Rings drafts from the 1940s, the form (ON.?) Rochan(dor) implies a different history for this name (RS/435).
The home of the Rohirrim, translated “Riddermark” (LotR/262) or more literally “Horse-country” (RC/241). It is a combination of roch “horse” and -(i)an “-land”, with the [[s|[x] (“ch”) softening to [h] in Gondorian pronunciation]] (LotR/1113).
Conceptual Development: In Lord of the Rings drafts from the 1940s, this land was first named N. Thanador of unclear meaning, which underwent several revisions (Ulthanador, Borthendor, Orothan[ador]) before Tolkien settled on N. Rohan (RS/434). At this earlier stage, Tolkien posited that this name developed from (ON.?) Rochan(dor); Tolkien coined the archaic form †Rochand later, while working on the drafts of the Lord of the Rings appendices (PM/53).