√NASAG root. “*bond, fetter”
A root in the Outline of Phonology from the 1950s, originally with a single derivative nazgwē > PQ nasque “evil spectre” (PE19/101 note #155). But in green-ink revisions from around 1970 Tolkien added two new derivatives Q. nasquë “bondage, durance” and Q. naxa “bond, fetter”, the latter with Sindarin cognate S. nadha (PE19/101). Tolkien added a note that it was likewise the basis of Black Speech nazg “ring” as an early loan from Common Eldarin, and it is clear this root was intended to be the basis for Nazgûl “Ring-wraith”.
Reference ✧ PE19/101