pullus.

Disputed; two etymologies are plausible: * From Proto-Italic *polnos, from Proto-Indo-European *polH-on- (“offspring, (animal) young”); compare Ancient Greek πῶλος (pôlos, “foal; young girl”), Proto-Germanic *fulô (“foal”), Albanian pjellë (“child”) and pelë (“mare”), Old Armenian ուլ (ul, “kid, fawn”). The verbal root is likely found in Albanian pjell (“to beget”), which implies a connection to pellō (“to drive, push”), from Proto-Indo-European *pelh₂- with a semantic shift of “to push (out)” > “to beget”, if not a distinct root *pelH- (“to give birth”). * From Proto-Indo-European *put-, also found in Latin putus (“boy”), Proto-Indo-Iranian *putrás (“boy”) and perhaps Sanskrit पोत (pota, “young animal”) (which would indicate *pewt-, though more likely borrowed from Dravidian) and Lithuanian putýtis (“young bird, young animal”). De Vaan reconstructs Proto-Italic *putslos, which he considers a variant of *putlos (“boy”). The presence of an earlier apical consonant in the stem in Latin is evidenced by the -s- in the diminutive adjective pusillus. Some authors connect these to the root *peh₂w- (“small”) (compare Latin paulus, paullus (“small”) and paucus (“little, few”), Old English fēaw (“little, few”)), but the morphology is unclear and the complete disappearance of the laryngeal is hard to explain. Alternatively onomatopoeic, like Swedish pulla.

Probably from Proto-Indo-European *polHwós (maybe a weak form of *pélHus) or *polHnós, from the root *pelH- (“pale, gray”), thereby related to palleō, though the formal details are debated.