Noldorin 

enedh

noun. core, centre, middle

While the word is written enedh in the Etymologies, it seems that Tolkien considered and reconsidered its form throughout his life. Late rough jottings (c. 1968), as well as the text of letter no. 168 and the fact that the toponym Enedwaith was never changed on the LotR map, seem to imply that ened is the (most) definitive form. See also the possibly related preposition ned , which has sometimes been suggested to mean "in" (while again a prefix nedh- is seen in the Etymologies)

Noldorin [Ety/356, Ety/376, UT/450, Letters/224, VT/41:12,] Group: SINDICT. Published by

enedh

noun. centre, middle, core

Noldorin [Ety/ÉNED; Ety/NÉD] Group: Eldamo. Published by

enedhin

proper name. Midyear week

A term for the Midyear week appearing in The Etymologies from the 1930s (LotR/LEP, EtyAC/LEP), apparently a combination of enedh “middle” and în “year”.

Noldorin [Ety/LEP; EtyAC/LEP] Group: Eldamo. Published by