Lake by which the Elves first awoke, a combination of nen “water” and echui “awakening”, corresponding to its more commonly used Quenya name Q. Cuiviénen (SA/cuivië).
Conceptual Development: In the Gnomish Lexicon from the 1910s, this lake was first named G. Nenin a Gwivros (GL/29), but appeared as ᴱN. Cuinlimfin in the Lays of Beleriand from the 1920s (LB/23). In notes associated with the Silmarillion drafts from the 1930s, it became N. Nen Echui (LR/406), a name that also appeared in The Etymologies (Ety/KUY). In Lord of the Rings drafts from the 1940s, Tolkien considered using Nenechui or Echuinen as an Elvish name of Mirrormere (TI/184), but later gave that lake the Sindarin name Nen Cenedril (RS/466).
A noun for “awakening”, most notably in Nen Echui “Water of Awakening” (SA/cuivië, LR/406). It appeared as N. echui(w) “awakening” in The Etymologies of the 1930s derived from primitive ᴹ✶et-kuiwē under the root ᴹ√KUY “come to life, awake” (Ety/KUY).
Conceptual Development: The earliest name for the “Waters of Awakening” was G. Nenin a Gwivros from the Gnomish Lexicon of the 1910s, and in that document G. cwivros “awakening” appeared as a noun form of G. cwivra- “awaken (intr.)” (GL/29). ᴱN. {cuibros >>} cuivros “awakening” appeared in Early Noldorin Word-lists of the 1920s (PE13/141) before the word became echui(w) in The Etymologies of the 1930s, as noted above.