Early Quenya
ilu
masculine name. Ilu
ilu
noun. ether
on(t)
noun. everything
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.
Shorter name of Ilúvatar (GL/50, LT1/61). It is probably related to ilu “ether”. In later writings it was likely replaced by Eru.