There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
enya
adjective. middle, *central, middle
enya
adverb. at some distant time, that far away
enyan(an)
adverb. then, at some distant time
A correlative appearing in Demonstrative, Relative, and Correlative Stems (DRC) from 1948 (PE23/109), a combination of ᴹQ. enya “that far away” and ᴹQ. -n(an) “time”.
ente
pronoun. [unglossed]
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
An adjective for “middle” in The Etymologies of the 1930s derived from ᴹ✶endya under the root ᴹ√ÉNED “centre” (Ety/ÉNED).
Neo-Quenya: For purposes of Neo-Quenya, I would instead use this word for “✱central” similar to the gloss of later entya. For “middle” I would use the later adjective Q. endëa.