From Proto-Tai *piːᴬ (“year”). Cognate with Northern Thai ᨸᩦ, Lao ປີ (pī), Lü ᦔᦲ (ṗii), Shan ပီ (pǐi), Thai ปี (bpii), Ahom 𑜆𑜣 (pii), Zhuang bi, Bouyei bil.
ᥙᥤ (pi) (old orthography ᥙᥤ)