From Middle Vietnamese ꞗĕải, ꞗải, from Proto-Vietic *k-paːs, from Proto-Mon-Khmer *kpaas (“cotton”); cognate with Muong pái, Bahnar kơpaih, Pacoh capaih, Khasi kynphad. Compare Sanskrit कर्पास (karpāsa) and Old Chinese 布 (OC *pˤa-s) (B-S), both of which are probably Austroasiatic loans. Doublet of bố (as in vải bố).
From Middle Vietnamese ꞗĕải, ꞗải. Compare Proto-Katuic *kpias (“lychee”) (whence Pacoh cupiêih).
Unlike what some modern sources seem to suggest, there is little to no evidence that lệ chi (荔枝 (lìzhī)) was used as a word for "lychee" in Vietnamese, even historically. This confusion is most likely due speakers' conflation between Written Chinese texts and actual Vietnamese texts.
(classifier cây, trái, quả) vải • (𣞻, 𣘓)