Early Quenya
polu
noun. kernel
polúne
noun. kernel
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 appearing as ᴱQ. polu or polūne “kernel” in the Qenya Lexicon of the 1910s under the early root ᴱ√POL-I (QL/75). In this document, the root was distinct from ᴱ√POLO “have strength” (QL/75).
Neo-Quenya: Although Tolkien did sometimes use √POL in his later writings for “grain” words, he seems to have eventually decided that it meant only “strength, physical ability”. I generally use ✱√MUL “grind” and ᴹ√POR for “grain” and “flour” related words in Neo-Quenya. As such I would update this Early Qenya word to ᴺQ. poru “kernel” < ᴹ√POR.