An adjective for “middle” in the Qenya Lexicon of the 1910s under the early root ᴱ√MEKE (QL/60).
Early Quenya
enya
noun. device (method, trick), machine, engine
meqa
adjective. middle
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.
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.
A word in the Qenya Lexicon of the 1910s glossed “device (method, trick), machine, engine”, based on ᴱ√ENE + ᴱ✶-yǝ whose derivatives had to do with devising and invention (QL/35). The parenthetical comment “device (method, trick)” seems to be for distinguishing its meaning from ᴱQ. enyarin “device, escutcheon, blazon” in the same entry.
Neo-Quenya: For purposes of Neo-Quenya I would update this word to ᴺQ. indya “device, machine, engine” as an elaboration of √IN(ID) “mind, thought”.