Middle Primitive Elvish
pher(en)
root. beech
bereth
root. beech
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 root in The Etymologies of the 1930s serving principally as the basis for N. brethil “beech” (Ety/BERÉTH). In the notes from the late 1950s or early 1960s Tolkien instead connected brethil to the root √BARATH and S. bereth “queen”, where it had the true meaning of “princess” (PE17/23). But that could be a later association rather that a genuine etymology, and doesn’t necessarily invalidate ᴹ√BERETH (especially given the other phonological issues with S. bereth < √BARATH).