Echoriath is Sindarin. It means "encircling fence", from echor "encircling" and iâth "fence". Christopher Tolkien mentioned that his father's intent was to rename the Echoriath as Echoriad, but perhaps this knowledge eluded him while publishing The Silmarillion. In his Unfinished index of The Lord of the Rings, Tolkien gave an alternate name for the Encircling Mountains: Eryd Echor, using the plural eryd of the Sindarin word orod "mountain".
Sindarin
echoriath
place name. Encircling Mountains, (lit.) Encircling Fence
Echoriad
Echoriad
Echoriad
place name. Echoriad (name)
eryd echor
place name. Encircling Mountains
The mountains around Gondolin, translated “Encircling Mountains” (S/138). This name is a compound of echor “encircling” (SA/echor) and iath “fence”, hence its literal meaning is “Encircling Fence”.
Conceptual Development: In the earliest Lost Tales, these mountains were called G. Heborodin “Encircling Hills” (LT2/166). In the tale “The Wanderings of Húrin” from the late 1950s, Tolkien changed the name to Echoriad (meaning unclear), but Christopher Tolkien retained the earlier but more common form Echoriath in the published version of The Silmarillion (WJ/271, 302 note 27).