Jabłko (n)
stock for the bellows
Pronunciation: "yapko"; Its name varies, according to its shape, which is in this case [in principle] spherical (➺ schematic drawing in Sobiescy).
Sobiescy, Jadwiga [Pietruszyńska] & Marian: Polska muzyka ludowa i jej problemy [Polish folk music and its problems]. Wybór prac pod redakcją Ludwika Bielawskiego [A selection of their works edited by Ludwik Bielawski]. Warszawa, 1973, p.86*, 87 & passim.