Middle Primitive Elvish
phelek
root. (animal’s) horn; steep mountain peak
pheleg
root. cave
gat(h)
root. *cave
rǭda
noun. cave
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.
An unglossed root in The Etymologies of the 1930s with derivatives like N. gath “cavern” and N. gador “prison, dungeon” (GAT(H)), so probably meaning something like “✱cave”. Its most notable derivative was N. Doriath “Land of the Cave”. But later on in this same entry, Tolkien added Doriathrin words Dor. gad “fence” and Dor. argad “outside the fence”, indicating a conceptual shift in the meaning of this root. Indeed, in later versions of The Silmarillion, S. Doriath was translated “Land of the Fence” containing the element S. iath “fence” (WJ/370, 378), so most likely ᴹ√GAT(H) “✱cave” was abandoned.