Qenya
lindornea
adjective. having many oaks
li(n)-
prefix. many
linin-
prefix. many
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 Etymologies of the 1930s glossed “having many oak-trees” or “having many oaks”, a combination of ᴹQ. lin- “many” and an adjectival form of ᴹQ. norno “oak”, where the more ancient initial consonant d- was preserved/restored in the compound (Ety/DÓRON, LI).