Sindarin name for Q. Estë, it is simply îdh “rest” used as a name, a derivative of primitive ✶ezdē (PE19/92).
Conceptual Development: The name N. Îdh appeared in The Etymologies from the 1930s, with the same derivation (Ety/EZDĒ). It was first written as (rejected) Ēdh, perhaps representing some uncertainty on the [[on|vocalization of [z] before voiced stops]] in Noldorin.
Estë is a Quenya name meaning "rest". The same Root, EZDE, also yielded her Sindarin name, Îdh (pron. [iːð]) and the Nandorin Eord.