In DN 23 we have in segment 32.2:
Tasmiṁ kho pana dāne evarūpaṁ bhojanaṁ dīyati kaṇājakaṁ bilaṅgadutiyaṁ, dhorakāni ca vatthāni guḷavālakāni.
At that offering such food as rough gruel with pickles was given, and heavy clothes with ball-tails. (Bhante Sujato’s translation)
The translator comments:
Read dhorakani, from dhura (comm thūlāni). For guḷavālakāni, cp. Kd 15 which has macchavāḷaka for a monk’s (forbidden) robe. It doesn’t make it particularly clear, but at least it’s something.
The most tricky word is guḷavālakāni, here rendered as “ball-tail”.
Even if I can relate to how he came to this translation, from the similarity with macchavāḷaka meaning “fish-tail”, as in this Vinaya passage about robe wearing styles that are not allowable (in Ajahn Brahmali’s translation):
hatthisoṇḍakaṁ, macchavāḷakaṁ, catukaṇṇakaṁ, tālavaṇṭakaṁ, satavalikaṁ.
in the elephant-trunk style, the fish-tail style, the four corner style, the palm-leaf style, and the hundred fold style.
But what is actually a ball-tail? Asking friends who are English native speakers, they couldn’t tell me, nor could any dictionary that I have consulted so far. Maybe Bhante @sujato can help solve the mystery?
Looking into the context, it is in the same line with “such food as rough gruel with pickles”, which is low quality food, so it is supposed to be a sort of low quality cloth or clothing.
My next thought went into how cloth is produced, and I thought I might find a hint there as to what constitutes a low quality cloth with something that should rather not be there.
Looking at the German Wikipedia page on spinning—which is much more detailed than its English counterpart—I find that before the actual spinning process, in the case of cotton the raw fibers need to be cleared of the remnants of seed capsules. We know that cotton was widely in use in India at the time of the Buddha—so could it be that guḷavālakāni are the remnants of seed capsules of cotton?
At least that would certainly make the resulting cloth low quality and would explain why the Brahmin student Uttara who was appointed to organize the offering wasn’t happy with what he had to distribute.