Name for the region of Air in Silmarillion notes from the 1930s (SM/236). It is simply vista “air as substance” used as a name.
Qenya
ilma
proper name. Starlight
vista
place name. Air
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.
This name first appeared in Silmarillion drafts from the early 1930s as ᴹQ. Silma >> Ilma >> Ilmen as a name for the “Place of Light”, home of the stars (SM/240-1). It reappeared in the mid-30s as a word for “Starlight” (LR/205), and also appeared in The Etymologies as a derivative of ᴹ√GIL, alongside (and perhaps an element of) Ilmen “region above air where stars are” (Ety/GIL).