A noun in the Qenya Lexicon of the 1910s glossed “bubble”, an elaboration of pumpo “bubble; bladder; blister” (QL/75). In the contemporaneous Poetic and Mythological Words of Eldarissa the word pumpole was glossed “bubble (a merboy)” (PME/75). It isn’t clear whether “a merboy” indicates that it was also the name of a character Tolkien intended to introduce (such as ᴱQ. Nardi “a flower fairy”, a name appearing in QL but nowhere else), or whether pumpole was term for a kind of sea-fairy, a masculine equivalent of ᴱQ. oaris “mermaid” or ᴱQ. wingild- “[sea] nymph”. I think the second scenario is more likely.
Early Quenya
pumpo
noun. bubble; bladder; blister
pumpole
noun. bubble; merboy
welbe
noun. bubble
A noun appearing as ᴱQ. ’welbe “bubble” in the Qenya Lexicon of the 1910s under the early root {ᴱ√WELE >>} ᴱ√GWELE (QL/103).
Neo-Quenya: For purpose of Neo-Quenya, I would adapt this word as ᴺQ. velvë with the usual sound change initial w to v. Both lb and lv appear in Quenya, but lv is the more common pronunciation (PE17/129).
A noun in the Qenya Lexicon of the 1910s with three meanings “bubble; bladder; blister”, appearing under the early root ᴱ√PUMU or ᴱ√PUPU (QL/75).